Priyanshu

Bihar Board Solutions for Class 11 English aids you to prepare all the topics in it effectively. You need not worry about the accuracy of the Bihar Board Solutions for Class 11 Read, Think and Enjoy Chapter 6 Of Remembering God Questions and Answers as they are given adhering to the latest exam pattern and syllabus guidelines. Enhance your subject knowledge by preparing from the Chapter wise Bihar Board Class 11th English Book Solutions and clarify your doubts on the corresponding topics.

Rainbow English Book Class 11 Solutions Read, Think and Enjoy Chapter 6 Of Remembering God

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Bihar Board Class 11 English Of Remembering God Textual Questions and Answers

Question 1.
Why do we remember God only in sorrow?
Answer:
It is human nature that we remember God only in distress. We pray to God to save and help us. On the other hand when we are in happiness we never remember god and forget Him. We are busy in earning more money and getting more pleasure. But Kabir Das says that if a man remembers and worships God is happiness, he can never be in sorrow, so a man should remember God at all the times.

Question 2.
Who, in your opinion, is greater-Guru or God? Why ? Discuss.
Answer:
Dear friends; we have gathered here to discuss over an important subject that who is greater-Guru or God. You many have different opinions on this issue. But so far think Guru is great her than God. He has created this earth. God is almighty, it is a fact, he is ommi potent and present every where. He is eternal. Guruis always present before us and is our guide. He is our well wisher. Kabir was also of the opinion that Guru is greater than God. According to him-Guru and God, both of them are present before him. He is in utter confusion, to whome he should give superiority and touch his fact first. But it is die greatness of Guru wo directed to bow-doiyn before God. It means to touch his (God’s) eet. God also becomes pleased with those who.pay respects to their. Guru, In case we are in trouble and loses our faith on God, gurti comes to our help. In means that a man should respect his Guru, then only God will helpus.

Question 3.
Talk to the people of different religions and find out the essential similarities between them.
Answer:
Talk with a Christian
Ajit: Well, Mr. John & what is your opinion about God.
John: God is all powerful. We are his creation. He helps us all.

Talk with a Muslim.
Ajit: Well Mr. Khan ! What do you know about Allh.
Amir Khan: We feel the present of Allah every where. He is estemal.

Talk with a Hindu
Amit: Well, Rahul gi, Give your view about Ishwar (God).
Kabul: Ishwar (God) always help us all, with out any in discrination. He extends his kind shelter to all the religions alike.

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Bihar Board Solutions for Class 11 English aids you to prepare all the topics in it effectively. You need not worry about the accuracy of the Bihar Board Solutions for Class 11 Read, Think and Enjoy Chapter 4 Lankapuri Questions and Answers as they are given adhering to the latest exam pattern and syllabus guidelines. Enhance your subject knowledge by preparing from the Chapter wise Bihar Board Class 11th English Book Solutions and clarify your doubts on the corresponding topics.

Rainbow English Book Class 11 Solutions Read, Think and Enjoy Chapter 4 Lankapuri

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Bihar Board Class 11 English Lankapuri Textual Questions and Answers

Let’s Think and Do :

Question 1.
How do the narrator and Manno behave with each other ? What does their behaviour signify? Is it common to all adolescents?
Answer:
The narrator and Manno behave with each other as if they are children and not grown-ups. Their relationship is more like a brother and a sister in a family. But they were neighbours. They were together for most of the time. They played with each other and like children they quarrelled. The narrater pulled her hair and hit her as if she was his small sister. In fact he never treated her as older than him though Manno was always conscious of it It appears they never realised that they were growing up. They played Nagintapu which is no game for adolescents.

In fact their behaviour with each other is unusual. It is not common to all adolescents.

Question 2.
Do you have any friend with whom you can be as free and informal as the narrator used to be with Manno?
Answer:
Answer this question yourself.

Question 3.
When the narrator comes out of Lankapuri, he becomes concious of the people staring at him and Manno. What does he become conscious of? What makes him conscious?
Answer:
The narrator has been into Lankapuri. When he went in he was an innocent child though he had grown into adolescence. In Lankapuri he saw the figure of naked girl, and some obscene words near it He had read similar obscene words on the wall behind his school and elsewhere. But he did not know what those words meant. But when he saw the naked figure of a girl, he lost his innocence. His adolescence was awakened in him. Now he was a changed person. He could not pull Manno’s hair as of old. His relationship with Manno was no longer the game of innocent children. Now when he saw. people staring at them, he became conscience that people did not look upon their being together in the lonely place as an innocent adventure. He understood people were looking at them with suspicion and disapproval.

Question 4.
At the aid of the story the narrator feds a knife pointed straight at his eyes. What does this image signify ?
Answer:
This image signifies that the people had murder- in their eyes. They were angry with the narrator because they believed he was immoral and deserved to be killed.

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Bihar Board Solutions for Class 11 English aids you to prepare all the topics in it effectively. You need not worry about the accuracy of the Bihar Board Solutions for Class 11 Read, Think and Enjoy Chapter 7 Letter To Cork Questions and Answers as they are given adhering to the latest exam pattern and syllabus guidelines. Enhance your subject knowledge by preparing from the Chapter wise Bihar Board Class 11th English Book Solutions and clarify your doubts on the corresponding topics.

Rainbow English Book Class 11 Solutions Read, Think and Enjoy Chapter 7 Letter To Cork

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Bihar Board Class 11 English Letter To Cork Textual Questions and Answers

Question 1.
Dean Mahomed says that an animal is commonly sold by measurement Does the practice continue even today ? How is elephant sold now ?
Answer:
No, the practice of selling an animal by measurement does not continue any longer.

An elephant is sold by bargaining. If the elephant is young, gentle, healthy and well-trained, it can fetch a good price. There are brokers who help to strike the bargain for a fee.

Question 2.
How many animals does the author describe in his letter ? Which are they ? Do they have anything common about them ?
Answer:
The author has described three animals. They are – the elephant, the rhinoceros, and the camel.

All these animals are large, bulky and strong.

Question 3.
Write a letter to your foreign friend describingyour favourite Indian animal.
Answer:
Dear Shashank.

I am glad to read the description of your favourite animal, the llama.

My favourite animal is the donkey, also known as the ass.

The donkey belongs to the horse family, but it is much smaller, It is about a metre high. It has long ears, thin legs and a bushy tail. It lives on grass which it crops with its sharp teeth.

I love a donkey because it is a symbol of humility and hard work. It cannot am fast like a horse. Of course, it does not look as graceful either. But it can cany heavy loads without complaint. It plays a vital role in our village economy. The dhobi or the washerman uses it to carry dirty clothes to the village pond or the river. While the washerman washes clothes, the hobbles his donkey and let it graze. In the afternoon he loads the donkey with washed clothes to bring home. ,

It is no less useful to the potter. He digs clay, and the donkey carries it to his house. He was the donkey to carry pots from one place to another, The donkey is also useful to the farmer to cany his produce to the market.

Indeed the unassuming donkey does a lot of work. But it is given very little to eat. It manages to browse here and there. My grandfather had a beautiful donkey. We have his picture in our drawing room. I am enclosing a copy of it for you to admire.

Yours sincerely

We believe the information shared regarding Bihar Board Solutions for Class 11 English Chapter 7 Letter To Cork Questions and Answers as far as our knowledge is concerned is true and reliable. In case of any queries or suggestions do leave us your feedback and our team will guide you at the soonest possibility. Bookmark our site to avail latest updates on several state board Solutions at your fingertips.

Bihar Board Solutions for Class 11 English aids you to prepare all the topics in it effectively. You need not worry about the accuracy of the Bihar Board Solutions for Class 11 Read, Think and Enjoy Chapter 5 Letter To Martha Questions and Answers as they are given adhering to the latest exam pattern and syllabus guidelines. Enhance your subject knowledge by preparing from the Chapter wise Bihar Board Class 11th English Book Solutions and clarify your doubts on the corresponding topics.

Rainbow English Book Class 11 Solutions Read, Think and Enjoy Chapter 5 Letter To Martha

Kick start your preparation by using our online resource Bihar Board Class 11 English Solutions. You can even download the Bihar Board Board Solutions for Class 11 Chapter 5 Letter To Martha Questions and Answers in Prison free of cost through the direct links available on our page. Clear your queries and understand the concept behind them in a simple manner. Simply tap on the concept you wish to prepare in the chapter and go through it.

Bihar Board Class 11 English Letter To Martha Textual Questions and Answers

Question 1.
Why and how do ‘The Clouds’ assume importance in prison ?
Answer:
The poet is inrison. In the prisonouse the are so many restrictions. The walls of the prison-house are very high. There are so many other obstacles to see the open sky. So the poet can not see the clouds in the sky freedly. the poet is very found of the beauties of the clouds moving in the sky and has a immense a great love for the beauties of nature. The motion of the clouds reveals such a melodious sound that the poet feel is like music, poetry and dance. The poet is prison cannot see the beauties of nature is the sky. He is auxious to know where the clouds are going and where they will be dissolved.

All these feelings of the poet about “the clouds” assume importance for the poet in prison.

Question 2.
Does the poem look at the nature or birds in the same way as does Nahru in ‘Animals in Prison’ ? Discuss.
Answer:
The poem, “Letter to Martha” looks at the nature or birds in the same way as does Nehru in ‘Animals in Prison’. The poet Dennis Brutus is in prison. He writes this poem while he is in prison. He loves nature very much He sees the beauties of the clouds, the birds and the stars in the sky. He is full of sorrow and grief that he is not enjoying the beauties of the nature sink he is in prison.

In the same way Pt. Nehru in his essay “Animals in Prison” looks at the nature. He has described the beauties of nature while he was in prison. His love for nature was beyond description. His gesture of love and respect tot he limiest animals was tremendous. Nehru’s heart moved by the beautiful sight of the “Himalayas”; Nehru was highly impressed to see the beauty of the spring. Dennis Brutas’s love for nature and bird is in the same way as does Nehru.

Question 3.
Can you remember any poem in any language that you know in which clouds pay a major role in the speaker’s life living in isolation. Translate, that poem in English and show it to your friends and your teacher.
Answer:
I remember a poem in Hindi language in which the clouds play a major role. The name of the poem is ”मेघ आए” written by Sarveshwar Dayal Saxena.

In the poem ”मेघ आए” the poet has described the beauties of Nature during rain. In this poem the poet has compared the clouds with a son-in-law (दामाद) who comes in the village wearing new and beautiful dresses is welcomed by the villagers. In the same way the clouds during rain look very beautiful and ‘ welcome by the people. They becomes equally happy when their son-in-law comes and when the clouds with water are seen in the sky.

All the men, animals and trees begin to dance in pleasure.

In this poem the nature has been personified. Hie air begins to dance to see the clouds and all the windows of the houses in the villages are being opened by the young ladies, when it is raining, the earth and the clouds are seen together as they are in love with one another.

So, in this poem the poet, has very beautifully described the beauty of nature.

We believe the information shared regarding Bihar Board Solutions for Class 11 English Chapter 5 Letter To Martha Questions and Answers as far as our knowledge is concerned is true and reliable. In case of any queries or suggestions do leave us your feedback and our team will guide you at the soonest possibility. Bookmark our site to avail latest updates on several state board Solutions at your fingertips.

Bihar Board Solutions for Class 11 English aids you to prepare all the topics in it effectively. You need not worry about the accuracy of the Bihar Board Solutions for Class 11 Poem Chapter 8 Follower Questions and Answers as they are given adhering to the latest exam pattern and syllabus guidelines. Enhance your subject knowledge by preparing from the Chapter wise Bihar Board Class 11th English Book Solutions and clarify your doubts on the corresponding topics.

Rainbow English Book Class 11 Solutions Poem 8 Follower

Kick start your preparation by using our online resource Bihar Board Class 11 English Solutions. You can even download the Bihar Board Board Solutions for Class 11 Chapter 8 Follower Questions and Answers in Prison free of cost through the direct links available on our page. Clear your queries and understand the concept behind them in a simple manner. Simply tap on the concept you wish to prepare in the chapter and go through it.

Bihar Board Class 11 English Follower Textual Questions and Answers

A. Work in small groups and discuss these questions :

Question 1.
How do people live in countryside ?
Answer:
The people living in countryside lead their life in a very simple way. They wear simple clothes. They have no television to entertain them. They lead their life in nature. They avail the privilege of nature. They work in field. They cultivate field. They grow corns, vegetables. They send all these things to market from where we buy all these things.

Question 2.
How is agriculture important for us ?
Answer:
Agriculture is important for us because we get cereals, pulse, vegetables, fruits, cotton and spices and so many other things from agriculture.

Question 3.
What do you understand by fertile soil ?
Answer:
Fertile soil bears bumper crops. If we have abundant crops, the economy of our country may improve. Our country may be economically sound. If the country is economically sound, it may compete in the field of science and technology with the advanced countries of the world.

Question 4.
Have you ever ploughed or seen a man ploughing ? Briefly narrate the experience.
Answer:
I have seen a man ploughing the field. The plough is made up of a wood and a sharp pointed tool of iron. Two bulls draw it. The farmer makes always pressure on the plough. Thus the field is ploughed.

B. 1. Answer the following questions briefly :

Question 1.
Why is the ‘father’ called an expert ?
Answer:
He is an expert person because he ploughs the horses perfectly well. The horses are well within his control. The horses become ready to work even if he directs them in a slow voice.

Question 2.
What did he look like ?
Answer:
He was looking like an expert, in the work of ploughing the field. His shoulder’s resembled the soil on the boats or ships.

Question 3.
How resolute was he at his work ?
Answer:
He was farmer and well determined at his work. He was very particular to guide horses with a long narrow strap around its neck, rolling over the field, watching them ploughing the field.

Question 4.
What was the observing when the was ploughing ?
Answer:
He was observing the narrow trench made by plough to see whether it was exactly done in a proper way. He was very particular in ploughing the field.

Question 5.
Why were his eyes ‘narrowed and angled’ ?
Answer:
His eyes were concentrated on the field and the horses, nothing else. He has done so to ensure that it was done properly. Narrowed and angles mean to concentrate over the movement of the horse and the work done.

Question 6.
What does ‘mapping’ suggest about his ploughing ?
Answer:
Mapping means the survey of the surface where the work was going on. Here it means the supervision and observance of the ploughing.

B. 2. Answer the following questions briefly :

Question 1.
What was the child doing while his father was at work ?
Answer:
The child was playing and making merry. Sometimes his father ride him on horse’s back. Again he was dipping and rising on the ground. Further he was following his father with slow heavy steps.

Question 2.
What did the child wish while following his father ?
Answer:
The child wanted to grow up and plough the field. He thought so to help his father.

Question 3.
How was the child a nuisance ?
Answer:
The child was a nuisance because he was stumbling and sometimes fell down.

Question 4.
Why does the father not go away ?
Answer:
The son has undertaken the work, his father was doing in the past. Now his father remains behind him and guides him in his work. His father has been a farmer. He has a wide experience of farming. The son has little knowledge of all these things. So he has to acquire knowledge to the same from his father. Father would remain behind him and guide.

C. 1. Long Answer Questions :

Question 1.
Who is the follower in the poem – the father, the son or both ? Explain.
Answer:
Seamus Heaney composed poem ‘Follower’ son is the follower of his father. The father took all care of his son when he was a child. He (father) worked in the field. He ploughed his field engaging horses for the purpose. At that time his son was a small child. He used to go along with his father there and play all day long. Sometimes his father ride him on the horse, sometimes on his shoulder. Now as he has become young he has taken up all the responsibilities of his father following his footsteps. So, he has become his follower.
Thus, it is clear that the son is the follower of his father.

Question 2.
Write a summary of the poem.
Answer:
The Seamus Heaney composed poem “Follower” is the live description a farmer father and his son. The son describes it in a most interesting ‘ manner. He narrates his farmer father’s style of doing a work. The father ploughs his field with the assistance of his horses. He does so to prepare his field for cultivation. He is very particular in discharging the work he has undertaken. He has concentrated his attention watching the movement of horses ploughing the field. His son has also come with him there. The child enjoys the pleasure of nature.

Sometimes his father rides him to horse’s back. He runs, a plays and often falls down in the field. Occasionally he follows his father, who is moving I with his horses, in the wide open field. Now as his father has grown old he wishes to take all his responsibilities. He wants that his father should talk rest and he (son) should work in his place. Now due to old age he stumbles, as he was stumbling in his childhood. It is his desire to follow his father’s working style. He wants to be his follower. In his childhood he was riding on his father’s back and shoulders now he wishes his father should stand behind him.

Question 3.
How does time influence the relationship between the son and the father ?
Answer:
Time is the greatest factor to decide everything and to find out the reality of life. We can not challenge this fact. It has been very well explained in the poem “Follower”. The father labours hard for the welfare of his family. He looks after his family. He works in the field, ploughs it through his horses and sows the crops in the farm. The child occasionally goes there with his father. He plays there all day long under his father’s guidance. Now he has grown up and the father became old. There comes a change in their routine work. The son being an young person now, undertakes the responsibilities of his family and the father leads a peaceful relaxed life. The son has taken up all care of his father.

Time has influenced relationship between both of them. Now the son has undertaken all those works his father was doing in the past. Father leads a peaceful life taking rest. It reflects in the poem that time has changed the life style of both, the farmer and his son.

Question 4.
Describe how the poet has ‘Conveyed the feeling of the farmer’s son.
Answer:
The poet Seamus Heaney has most beautifully conveyed the feeling of the farmer’s son in his poem “Follower”.

He remembers his childhood days when his father was labouring hard, day and night, to met out the requirement of his family. He has given entire affection to his son. He had done hard labour to cultivate his field and never took perfect rest. He was engaged in his work throughout the year. He had done everything what his son asked for in this childhood. The son feels highly obliged and indebted of his father sacrifices. Now as he has become a grown up young man, he wants to relieve his father from all his duties and responsibilities and to do all those work what his father (the farmer) had been doing. He wants to follow him, properly in life. He intends to become his follower.

C. 2. Group Discussion :

Discuss the following in groups or pairs:

(a) How can we improve our agriculture ?
(b) Low income of farmers is a cause of great concern in India.
(c) Generation gap.
Answer:
(a) The essential requirements to improve the agriculture are : high yielding seeds, natural fertilisers. Besides these we should use modem devices and scientific methods. The small pieces of lands should be brought together to make a big piece. Co-operative method should be adopted for working. The Government should also provide necessary assistance specially in irrigation. Trained agriculture specialists should be employed to make the farmers aware with the modem technology of agriculture.

(b) Low income of farmers is caused by
(i) Traditional method of agriculture.
(ii) Natural disaster-flood and draught.
(iii) Lack of proper planning and attention by the government.
(iv) Low price of their products.
(v) Seasonal employment in agriculture.
All the above factors affect the economy of India.

(c) Generation gap sometimes creates confusion. With change of time the values of society change. The older and matured people have their own point of view for life which cannot match to the point of view of the younger generation. The younger generation believes in modem and scientific living. The older generation does not consider such type of living proper according to the religion and morality. They give greater importance to their own old life style. Sometimes these differences create conflict. Though both the generations should realise the feelings of each other.

C. 3. Composition :

Write a paragraph in about 100 words on the following:

(a) Use of chemical fertilizers.
(b) Use of modern techniques in farming.
Answer:
(a) Chemical fertilizers are used in our agriculture to inhance the products. Chemical fertilizers give higher production. They are frequently used by the farmers as they can earn much by selling the products. The products also look very nice and developed. But they are not so much good for health. The chemical fertilizer also damages the land. Land begins to be desert bit by bit. The amount of fertilizer which we use this year, we have to use more than this amount. On the other hand natural fertilizer cannot enhance the product so much in the comparison of the chemical fertilizer but natural fertilizer maintains the fertility of the land. It is also cheaper than the chemical fertilizer. But from business point of view natural fertilizer is so much fruit bearing.

(b) India is an agricultural country. More than its 70% population are engaged in agriculture. But most of them are uneducated. They use the traditional way of agriculture. Traditional way of agriculture is not so much effective. Modem techniques are less time taking and highly productive. Modem techniques include-tractors, high yielding seeds and scientific way of sowing the seeds or seedlings. The farmers should also know what type of land is required for particular crops. There are so many machines used for different kind of works in agriculture. For irrigation pumpsets are available which run on motor. Threshers are used to separate grains from husks. There is also a machine available for harvesting the crops. Thus in minimum time maximum works can be done with a very low man power. But for all these things the farmers should be educated.

D. Word Study:

D. 1. Dictionary Use

Ex. 1. Correct the spelling of the following words
tonge sweting stifen stmbing diping
Answer:
Tongue Sweating Stiffen Stumbling Dipping

Ex. 2. Use the following nouns as verbs:
eye map ground nail fall shadow
Answer:
Eye-My father eyed my activities in the party.
Map-The engineer mapped the plane.
Ground-Our ship grounded on the port.
Nail-Christ was nailed on cross.
Fall-The man fell on the slippery road.
Shadow-The evil force shadowed my house.

D. 2. Word-Formation :

Read the following sentences carefully :

My father worked with a horse-plough ……………
I stumbled in his hob-nailed wake ……………

You see that in the first sentence a compound word ‘horse-plough’ is made by combining two nouns ‘horse’ and ‘plough’ and it functions as a noun. In the second sentence the compound word ‘hob-nailed’ consists of a noun ‘hob’ and ‘nailed’ and it functions like an adjective. Several compound words can be made by combining two similar or different parts of speech. Now form as many compound words as you can by using words given below a different ways. You may use derivaties of the same word, e.g. break + fast = breakfast.

Answer:
Fast – breakfast, steadfast, fast-friend.
Point – pointout, pointguard, melting-point.
Break – breakdown, breakfast.
Conscious – non-conscious, unconscious, sub-conscious
Write – writeback, write-off, writing-pad.
Heart – heart attack, heart beat
Match – matchbox, matchmaker
Colour – colourblind, colour code
Fit – fitfully, fitness, unfit
Blank – blankcheque, blankverse
Steel – steeldrum, steelworks, steelbar
Melt – Meltdown, melting point
Look – Lookout, looking-glass

D. 3. Word-Meaning :

Find from the poem words the meaning of which have been given in ‘Column A’. The last part of each word is given in ‘Column B’:

Answer:
1. plod
2. nuisance
3. yapping
4. wake

D. 4. Registers :

Ex. 1. Find out the words from the poem which are used in agriculture :
Answer:
plough, shafts, furrow, sock, sod, land farm.

Ex. 2. Write 10 words which are used with specific meanings in film- industry.
Answer:
box-office, film; star, director, producer, audience, location, shootings, coverae, outdoor, script, make-up, actor, villain, flop, set, costume.

E. Grammar :

Examine the following forms of the verb ‘go’ carefully:

Ex. Give different forms of the given verbs as illustrated above:

Answer:

F. Activity :

What kind of plough is used in your village / locality ? Trace out its origin and other details by talking to the elderly people in your family / society. Do a project work on plough.
Answer:
In my village most of the people are poor and uneducated so they use traditional plough. Traditional plough is made up of wood and sock. It is a traditional equipment which is in practice since the beginning of the human civilization. Now its substitute is a tractor. But all farmers cannot afford to buy tractor. Mannual ploughing is a long process. It takes too much time to plough the whole field. It requires a pair of bulls or horses which draw the plough. Tractor ploughs the field in a very short time and in a better way. It does not require any animal or plough. It requires petrol or diesel, a number of socks to till the field.

We believe the information shared regarding Bihar Board Solutions for Class 11 English Chapter 8 Follower Questions and Answers as far as our knowledge is concerned is true and reliable. In case of any queries or suggestions do leave us your feedback and our team will guide you at the soonest possibility. Bookmark our site to avail latest updates on several state board Solutions at your fingertips.

Bihar Board Solutions for Class 11 English aids you to prepare all the topics in it effectively. You need not worry about the accuracy of the Bihar Board Solutions for Class 11 Prose Chapter 6 I Pass the Delhi Test Questions and Answers as they are given adhering to the latest exam pattern and syllabus guidelines. Enhance your subject knowledge by preparing from the Chapter wise Bihar Board Class 11th English Book Solutions and clarify your doubts on the corresponding topics.

Rainbow English Book Class 11 Solutions Chapter 6 I Pass the Delhi Test

Kick start your preparation by using our online resource Bihar Board Class 11 English Solutions. You can even download the Bihar Board Board Solutions for Class 11 Chapter 6 I Pass the Delhi Test Questions and Answers in Prison free of cost through the direct links available on our page. Clear your queries and understand the concept behind them in a simple manner. Simply tap on the concept you wish to prepare in the chapter and go through it.

Bihar Board Class 11 English I Pass the Delhi Test Textual Questions and Answers

A. Work in small groups and discuss the following questions :

Question 1.
Do you play cricket ? How much do you like it ?
Answer:
Yes, I play cricket. I like it very much.

Question 2.
Where and how did the game of cricket originate ?
Answer:
Cricket developend in the early 18th century from the ‘bat and ball’ game played a century earlier, mainly by boys. Its rules were formulated by the Maiylebone Cricket Club (MCC), which was founded in 1787 and was for many years the governing body of the game.

Question 3.
How many countries play Test Cricket ? Can you make a list of these countries ?
Answer:
Ten countries play Test Cricket. The following countries play Test cricket: Australia, New Zealand, South Africa, India, Pakistan, Sri Lanka, West Indies, England, Zimbabwe, Bangladesh.

Question 4.
What is the difference between a Test Match and a limited over one day match ?
Answer:
A Test Match usually goes on for five days. There is no limit to overs. A team can go no batting till it is out or it decides to declare. A one day match is limited usually to 50 overs and it is only one day show.

Question 5.
Which form of cricket do you like more ? Give reasons.
Answer:
I like a Test Match. It is more interesting and each team/player has a chance to display its best.

B. 1. Answer the following questions briefly :

Question 1.
Which boook of Gavasker was released on the eve of the test ? Who released the book ?
Answer:
Gavaskar’s second book Idols was released on the eve of the test. It was released by Kapil Dev.

Question 2.
Who was the chief guest ? Who were the other important guests ?
Answer:
Clive Lloyed was the chief guest. Michael Holding and Jeff Dujon were the other important guests.

Question 3.
Gavaskar could not take good rest, as he had intended. Why ?
Answer:
Gavaskar went to his hotel to rest. But his wife’s friend Bijoya, her sisters and brothers with their spouses came to see them. A party was immediately arranged. So Gavaskar could not take rest.

Question 4.
‘Within hours the battle was to be resumed, so we went back to the hotel to rests.’ What does the ‘battle’ refer to ?
Answer:
The battle here refers to the Second Test in Delhi.

Question 5.
Why did Gavaskar leave the nets early during practice ? What was Kapil’s reaction ?
Answer:
Gavaskar was upset because a part of the crowd had passed nasty remarks on him. He left the nets early because he wanted to keep him cool and relax.

Kapil did not like Gavaskar’s leaving the nets but he did not say anything.

Question 6.
What did the young girls ask Gavaskar ? Why did he laugh at their request ? What does it suggest about the level of his confidence ?
Answer:
The girls asked Gavaskar to score the fastest century of his career. Gavaskar laughed at their request because he did not hope to score even half a century. This shows that his level of confidence was very low.

Question 7.
How far, do you think, is it proper to make derisive comments when a good player is struggling to regain his form ? Does it help the player anyway ?
Answer:
It is improper to make derisive comments on a player who is struggling to regain him from, but spectators expect good game. When they are disappointed resort to criticrse a player. Such they comments seldom help the player. He is only demoralised.

Question 8.
A couple of messages meant a lot’ What does Gavaskar mean by this ?
Answer:
Gavaskar means to say that a couple of messages were sufficient to cheer him up. He felt relaxed and encouraged.

Question 9.
How do you feel when your friends or relatives offer their best wishes when you are getting ready for exams ? Does it help you any way ?
Answer:
Yes, good wishes and words of cheer do help me to feel better.

Question 10.
What are your feelings on the eve of an important examination ? Do you feel any sort of anxiety even after a good preparation ? If so, why ?
Answer:
An examination naturally causes anxiety. Inspite of good preparation, I do not feel that I am fully prepared to face it.

B. 2. Answer the following questions briefly :

Question 1.
Why was Gavaskar finding it easy to play ?
Answer:
Gavaskar found it easy to play because he was feeling relaxed. Secondly, Delhi wicket is favourable to batting.

Question 2.
Give two instances when luck favoured Gavaskar during the match.
Answer:
Gavaskar was lucky twice. Once when he was 16, he missed the shot. The ball brushed his hat. The umpire did not signal anything. Perhaps he was misled by the sound of the ball brushing Gavaskar’s cap. Gavaskar got some runs.

Again, he hit a ball off the middle. It went quite high. A tall fielder like i Roger Harper or Joel Gamer could have leapt and caught it. But the fielder was not so tall. Gavaskar got six runs.

Question 3.
What is ‘another hurdle’ Gavaskar talks about ?
Answer:
No player would like to score a duck, that is zero. This means one is going to be a utter failure. It is a hurdle and Gavaskar crossed it when he had got a couple of runs after Marshall’s third ball.

Question 4.
“I don’t look at the scoreboard or the clock when I am batting.” What light does it throw on Gavaskar’s way of batting ?
Answer:
It shows that Gavaskar wanted to play the game in a relaxed manner unmindful of his score. He was more relaxed like this than he was if he were aware that he was close to a century.

Question 5.
“Bloody-hell! It’s your twenty-ninth.” Who said this ? What does the ‘twenty-ninth’ refer to ? Why did it bring delight to the countrymen ?
Answer:
This was said by Dilip Vengasarkar ‘Twenty-ninth’ refers to the 29th century scored by Gavaskar. It broght delight to the countrymen because they were eagerly waiting for it to happen.

Question 6.
How does applause help a performer ? Have you ever experienced it ?
Answer:
Applause gives delight to the performer. He feels he has been rewarded for his performance. Once I experienced it when I delivered a speech in the school assembly.

Question 7.
Which one did Gavaskar consider to be his best test century and why?
Answer:
Gavaskar considers his best test century that he scored in the first I test at Old Trafford in 1974. He considers it the best because batting conditions there were against batting, and it had come after three and a half years.

C. 1. Long Answer Questions :

Question 1.
‘Right’ Today you bounce and I am going to hook.’ What does it suggest about Gavaskar’s plan to tackle West Indian bowling ?
Answer:
It shows that Gavaskar planned his strategy correctly, and it helped him to score quickly.

Question 2.
‘I do not think I have ever played so many shots to get a century. I Most of my centuries have a liberal sprinkling of ones and twos and take their time coming and this was definitely the quickest in terms of time as well as deliveries faced.’ Does the statement suggest any change in Gavaskar’s batting in his particular match ? If yes, what kind of change is suggested here ?
Answer:
This shows that Gavaskar had been slow at making runs. He had hardly shot sixers and fours before. He got ones and twos. But in the Delhi Test he must have shot sixers and fours. That is why he made mns quickly by facing fewer deliveries.

Question 3.
Pick up sentences as the ones quoted in the earlier two questions and evaluate how far it is justified to say that Gavaskar was a good planner of the game.
Answer:
The following sentences show that it was not Gavaskar’s planning that helped him but a couple of chances. When he was at 16 he could have been injured but he got some runs. He might have been caught out if the fielder was tall enough to leap and catch the ball.

(i) When I was 16, a bouncer came ………………….. and I missed my shot, but luckily ball brushed my hat ………………….. The umpire did not signal anything the umpire was misled by the sound of the ball brushing my cap ………………….. I got some runs.

(ii) The second alarm came when I hit the ball off the middle but it went – at a height where Roger Harper Joel Gamer could have leapt and caught the ball. Fortunately, the fielder was not as tall as those and I got six runs instead.

Question 4.
Notwithst anding that it was his quickest century, Gavaskar does not think it was his best century Why ?
Answer:
He considers his best century that he scored at Old Trafford in 1974. The century he scored at Delhi came easy. But the one at old Trafford was difficult. Conditions there were against batting, and he had not scored a century for over three years. He doubted his ability to score. This century gave him a new lease of his career.

Question 5.
How much did the countrymen admire and love Gavaskar ? Give evidence from the lesson.
Answer:
Countrymen admired Gavaskar. Some young girls asked him to score the fastest century of his career. He got a few messages wishing him success at the test match. In fact, since his return from West Indies, people were eager for him to score the 29th century. Where he went they offered him their good wishes. They had eagerly waited and prayed for it.

Question 6.
‘Crowds allover India are basically the same and are particularly adept at kicking a man when he is down.’ How far do you agree with Gavaskar’s observations ? Can you cite examples-from cricket or eisewhere-in favour of or against the observation ?
Answer:
I do not agree that Indian corwds criticise a player when he is down. In fact, there is hardly any sportsman spirit anywhere in the world. Players play to win because there is much money involved. Audience do not appreciate the game. They seldom praise a good player of a team playing against their country. They want victory for their team.

When their team is not doing well, they are disppointed, and become restless. There are examples when audience broke into the field and smashed everything. Sometimes they even accuse the umpire of being partial. Gavaskar himself confesses that his countrymen loved and admired him. I think the man that criticised for his play also loved him and had great expectations.

Question 7.
Who among the modern cricketers, in your opinion, show the kind of concentration and application that Gavaskar used to show ?
Answer:
I think Tendulkar shows the same concentration and application as Gavaskar used to show.

Question 8.
‘Offence is the best strategy of defence.’ How does Gavaskar’s century prove this ?
Answer:
Marshall threw a bouncer which Gavaskar hooked. At first Marshall frowned and then smiled cunningly. He had planned his offence. But Gavaskar did not think of playing safe. He decided to hook every ball and send it flying to the boundary. In this way by offensive strategy he scored a century.

Question 9.
A good autobiography is honest. The author describes success and admits failures, accepts blame and claims credit. In what ways do you think Sunil Gavaskar is honest in writing about his experiences ? Use specific references from the lesson as examples.
Answer:
Gavaskar has described his feeling honestly. He has confessed that he whs upset when a part of the crowed citicised him for his bad play. He went away to keep cool. He also tells us about his lack of confidence before the test began.

He honestly tells us how he was lucky when he was at 16 and when he was about to be caught out. He does not claim credit for those scores. But he also tells us how easy he found to score runs. We also learn that he did not look at clock or the scoreboard during the game. Some people may consider it his’ superstition but he says he does so to avoid tension. He is critical of the crowds in India but he also owes gratitude to them for their love and appreciation and good wishes that helped him to score the 29th century.

C. 2. Group Discussion :

Discuss the following in groups or pairs :

Question a.
Fortune favours the brave.
Answer:
Hints : Many people believe in fate or luck. But luck comes to those who act. If a person is a coward and runs away from action, how can luck favour him. Many people avoid action because they are afraid of the consequences. Indeed action means risks and dangers. But those who dare, win. Fortune favours them. Those who run away lose and suffer. Ill luck dogs them.

Question b.
Modelling affects sportsperson’s performance.
Answer:
Hints : These days players are highly paid. Business companies want successful and popular sportspersons to promote their sales. So they appear on products and on mass media. They are paid well for this. Allurement of money makes them to. modelling. They have to give sufficient time for the shooting of a commercial. Naturally they cannot pay full attention to game and their performance suffers.

C. 3. Composition :
Write a paragraph in about 100 words on each of the following :

Question a.
The sportperson you like most
Answer:
I am found of playing chess and Vishwanathan Anand is the sportsperson I like most. He is the current world Champion and has done his country proud.

Anand was bom in 1969. He picked his early lessons in chess from his mother at the age of six. In 1984 he became the youngest Indian to win the International Master title at the age of fifteen. Next year he became the National Champion. He became India’s first Grandmaster in 1988.

Anand won the FIDE World Chess Championship in 2000 for the first time after defeating Alexei Shirov in the final match held at Tehran. He became Chess World Champion again by winning the FIDE World Championship Tournament held in Mexico City. He is one of four players in history to break the 2800 mark on the FIDE rating list.

He was awarded the Padma Bhushan in 2000.

Question b.
Performing in unfavourable condition is the test of a genius.
Answer:
Everyone can perform under favourable conditions. And chose who do so seldom go down in history. We admire and remember only those who do something great in difficult and unfavourable conditions. Abraham Loncolon wanted to abolish slave trade from America, and set the Negroes free. The southern states were against him. There was the risk of the disintegration of the country.

But Lincoln was determined to do this noble work. He did it and the world acknowledges him as a champion of liberty and democracy Gandhiji tried to liberate the peasants from the tyranny of the British landlords in Champaran. Conditions were unfavourable. But he did wonders and liberated the peasants from the fear of the British oppression. The world looks upon him as a great genius.

Question c.
Where there is will there is a way:
Answer:
Most of us find excuses when we do not have the will to do something. We can count a number of hurdles and difficulties that make accomplishment impossible. But poeple who have strong will achieve that looks impossible to others. Napoleon said that word impossible was found in the dictionary of fools. People with strong determination have climbed up Everest, reached the south pole, crossed the Atlantic on a raft. Columbus sailed to the unknown continent. People with will have achieved what they wanted to achieve. Nothing is difficult if we have the will If we have the will we will find ways, wide open to Welcome us.

D. Word-Study:

D – 1. Dictionary Use :

Ex – 1. Correct the spelling of the following words :

Answer:

Ex – 2. Look up a dictionary and write two meanings of each of the following, words the one in which it is used in the lesson and the other which is more common :

Answer:
look : (i) to turn eyes in a particular direction.
(ii) to watch a game.

fnction : (i) a special activity or purpose of a person.
(ii) a social event or ceremony.

plan : (i) something that one intend to do or achieve.
(ii) a detailed map of a building

Strident: (i) unpleasant sound.
(ii) aggressive and determined.

name : (i) a word or words that a particular person, animal, place or thing is known by.
(ii) a reputation that somebody has.

Surprise : (i) an event, piece of news that is unexpected or that happens suddenly.
(ii) to surprise somebody suddenly in a way that slightly shocks or frightens him.

Test: (i) test match.
(ii) an examination

Lease : (i) the chance to live or last longer.
(ii) a legal agreement that allows one to use building or some land for a period of time.

D. 2. Word-meaning :

Ex-1 Find from the lesson words the meaning of which have been given on the left hand side. The last part of each word is given on the right hand side:

1. a big smile that sows your teeth : …………………. in
2. skiful at doing something ………………….
3. to someone in am angry way. ………………….
4. the time a performer or player appears in public ………………….
5. an event or achievement that marks an important stage in a process: …………………. stone
6. an expression on your face by moving eye-brows : …………………. own
7. to push someone or something with force …………………. ove
8. the act of throwing a coin into the air in order to make a decision …………………. ss

Answer:

1. grin
2. adept
3. inside
4. debut
5. milestone
6. frown
7. shoved
8. toss

D. 4. Phrases :

Ex-1 Read the lesson carefully and find out the sentences in which the following phrases have been used. Then use them in sentences of your own.
drop in, at times, look after, pick up at ease
Answer:
The sentences in the lesson in which the phrases have been used :
Bijoya, dropped in to see her. (Para-2)

………………. a skipper gets a suite and so is able to look after his gues better. (Para-2)
………………. having informed Kapil that rather then pick up a fight with the crowd (Para-4)
………………. I was feeling relaxed and completely at ease. (Para-5)
………………. and at times chided me during my career. (Para-5)

drop in – Ramesh dropped in to see me.
at times – He used to threaten me at times.
look after – She is able to look after her children.
pick up – He must not try to pick up a fight with them.
at ease – She feels relax and completely at ease.

E. Grammar :

I had left the net. He had won the toss.
In the above examples, the sentences are in Past Perfect Tense.
Change the following sentences into Past Perfect Tense.

1. I read a book.
2. He cleans the floor.
3. They have played for India.
4. You will do the work.
5. The boy is eating a mango.

Answer:

1. I had read a book.
2. He had cleaned the floor.
3. They had played for India.
4. You would have done the work.
5. The boy had eaten a mango.

F. Activity :

Ex – 1. Registers :

Words like run, pitch, cover are used in special sense in cricket. In other words, they are the registers of cricket Read the lesson carefully and And out the registers of cricket used in the lesson. Find out the meaning of each of these registers with the help of your game-teacher or reference books/dictionaries.
Answer:
Run – score
Pitch – an area of ground specially prepared and marked for playing a game.
Cover – to spread the ground.

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Bihar Board Solutions for Class 11 English aids you to prepare all the topics in it effectively. You need not worry about the accuracy of the Bihar Board Solutions for Class 11 Prose Chapter 8 Mother India Questions and Answers as they are given adhering to the latest exam pattern and syllabus guidelines. Enhance your subject knowledge by preparing from the Chapter wise Bihar Board Class 11th English Book Solutions and clarify your doubts on the corresponding topics.

Rainbow English Book Class 11 Solutions Chapter 8 Mother India

Kick start your preparation by using our online resource Bihar Board Class 11 English Solutions. You can even download the Bihar Board Board Solutions for Class 11 Chapter 8 Mother India Questions and Answers in Prison free of cost through the direct links available on our page. Clear your queries and understand the concept behind them in a simple manner. Simply tap on the concept you wish to prepare in the chapter and go through it.

Bihar Board Class 11 English Mother India Textual Questions and Answers

B.1. Answer the following questions briefly :

Question 1.
To whom has Subhash written the letter and on what day ?
Answer:
Subhash wrote the letter to his mother on the day of Durga Puja.

Question 2.
Was Subhash writing this letter in happiness ? If not, why ?
Answer:
No, Subhash was not happy when he was writing this letter. He was sad because he was away from his family on the sacred day of Durga Puja.

Question 3.
“He has been born in this great land in every age…….” Who does ‘He’, here, stand for ?
Answer:
Here ‘He’ stands for God.

Question 4.
Why does Subhash call India God’s beloved land ?
Answer:
Subhash calls. India God’s beloved land because He appeared in India many more times than in any other land.

Question 5.
Give the description of the Indian seasons as described by Subhash.
Answer:
According to Subhash India has hottest summer, severest winter, the heaviest rain and most heartwarming autumn and spring.

Question 6.
Discuss the significance of the river Ganga in our life.
Answer:
The Ganga carries away the filth of the world. It purifies our minds and bodies. It has inspired our yogis and saints to gain spiritual enlightenment.

B.2. Answer the following questions :

Question 1.
According to Subhash why is Mother India unfortunate ?
Answer:
According to Subhash Mother India is unfortunate because she does not have one single selfless son.

Question 2.
What does Subhash mean by “hoary past” ,
Answer:
Subhash thinks of ancient Indian civilisation. It was a glorious civilisation with great thinkers. But now that glory seems to have been lost.

Question 3.
Subhash calls himself and the people of India selfish. Why ?
Answer:
The condition of our country is going from bad to worse. But people of India including Subhash, are so selfish that none of them dedicates his life to the cause of motherland.

Question 4.
Why can a mother never be selfish ?
Answer:
A mother can never be selfish. She loves all her children and she lives for her children.

Question 5.
What happens when a mother sees her children in sorrow ?
Answer:
A mother is moved at the plight of children. She sheds tears.

Question 6.
What are the causes of the misery of people ?
Answer:
Ignorance, blind faith and bigotry are the reasons of the misery of people.

Question 7.
What things have made the existence of Indian people “a veritable Hell ” ?
Answer:
Hunger, lack of love, jealousy, and selfishness have made the existence of Indian people “a veritable Hell”

C.1. Long Answer Questions:

Question 1.
In the letter it appears that Subhahs is arguing with his mother. He repeatedly asks her questions. What are these questions ? Why does he repeatedly ask questions ?
Answer:
It was the day of Durga Puja. Durga is a mother goddess. Subhash was away from home. He is thinking of his mother as well as his motherland. ’ He is pained to see the pathetic condition of India under the British rule. He thinks of India’s past glory. He thinks that it is the duty of the sons of a mother to help her and serve her. But the people are so ignorant and selfish that they are concerned only about themselves. There is bigotry, ignorance and lethargy. Subhash wonders why mother herself is not moved to tears at the pitiable condition of her sons. He repeatedly asks her these questions. Subhash himself wants to serve his mother land. But he thinks he himself is not yet ready to take the plunge.

Question 2.
Write a short note on the piousness and sacredness of the river Ganga.
Answer:
The Ganga is the symbol of our civilisation and culture, our faith and devotion. Since ancient times the Aryans of India have lived along her banks. Our great saints and sages set up their ashrams on her banks. Ganga flows all the years round. Her water is looked upon as nector. People far and wide, who visit her, carry back gangajal with them.

It is needed on all holy and religious ceremonies. Even today thousands of people visit the Ganga every day. Yogis and munis still have their ashrams along its holy banks. Our association with Ganga goes back into the hoary past. Ganga is the most sacred of our rivers.

Question 3.
Change this letter into a diary entry.
Answer:
Saturday
Cuttack

Dear Diary,

Today is Durga Puja and I am away from home. I’m thinking of my mother. I wish I were with her.

But I am also thinking of the pitiable condition of my motherland. I wonder why people are so self-centred that they do not bother about doing something for their motherland. We are quarrelling among ourselves over petty matters. We are selfish and ignorant. We are lazy and heartless.

I am sure some great soul will rise and lead the country to salvation. God has appeared again and again to lead the people from darkness into light. He will appear again.

But I resolve this day that I must do something for my mother land. I hope that time is not far away.

Question 4.
The letter creates a picture of Subhash’s personality – his love for his mother as well as for his motherland. Discuss Subhash as a son.
Answer:
The letter clearly reflects Subhash’s love for his mother. It is the Durga Puja day and he is away from home. He suffers from the agony of separation from his mother.

He looks upon his mother as the mother of all. She has been to many places in India and seen the pitiable condition of the people. He wonders why she is not moved to tears. Subhash thinks of the motherland. Her condition is going from bad to worse. He is pained. He feels an urge to serve his motherland. He wishes to dedicate his life to her cause. He is determined to do so. He is a true son of his mother as well as his motherland.

C.2. Group Discussion :

Discuss the following in groups or pairs:

Question a.
Mother can never be selfish.
Answer:
(Hints for discussion)
A mother is a symbol of sacrifice. She lives for her children. She would starve but would not her children go hungry. Some children treat their mother ill. Even then she forgives them. She would not like to see that any harm comes to her children.

Question b.
We cannot repay our mother’s love.
Answer:
We all are deeply indebted to our mothers. Her love is boundless. She makes every sacrifice for her children. If a child falls ill, mother would not go to sleep. If her child is late in coming home, she is worried. Whatever we may do, we cannot repay the love of our mother.

C.3. Composition :

Question a.
Write a letter to your father describing how you feel about Subhash. Do not exceed 100 words.
Answer:
23 January 20

My dear Father,

Today we celebrated Netaji Subhash Chandra Bose’s birthday in our school. I have learned a few things about his zeal for the unity and independence of India. He left India and went to Germany. He went to Japan. He led the Azad Hind Fauj against the British to liberate India I have a deep respect for him. Though he did not live to see India’s independence but it was. His dream that came true. He did not believe in pomp and show but in true devotion and hard work.

I look upon him as my role-model.
With regards to mother.
Your loving son
Rishikesh

Question b.
Write a short paragraph in about 100 words discussing your love for nation.
Answer:
Today India is a free and independent nation. But this freedom came to us as a result of the sacrifices of millions of dedicated men and women of our country. I think that I have a duty to serve my motherland. I am yet not sure how I shall serve her. But I love her as I love my mother. To serve motherland and I don’t need to be a minister or a military officer. I think I will serve her if I do my duty honestly in whatever position I am. India is a great country and now she is on the right track to achieve her pride of place among the nations of the world.

D. Word-Study :

D-1. Dictionary Use:

Ex – 1. Correct the spelling of the following words :

Answer:

Ex – 2. Pick out the words which show Subhash’s agony.
Answer:
pang, pining, deplorable, bigotry, wailings, stupor, lethargy.

D. 2. Word-meaning:

Ex – 1. Match the words given in Column-A with their meanings in Column-B

Answer:

D.3. Phrases:

Ex – 1. Read the lesson carefully and find out the sentences in which the following phrases have been used. Use them in sentences of your own :

Answer:
It is enough if we invoke the one we seek to attain with all our heart and in all sincerity;
….On the immersion day but at heart I shall be with you all.
….to rid this earth of sin and to establish righteousness and truth….
He has come into being in many countries in human form….
….I am reminded of another scene, the yogis have collected on its bank….
….and so pleasing to the eyes as well as to the mind.
A mother can never be heartless !
That can never be.
If that be so, how is that mother is unmoved when her children are suffering.
….our country continue to go from bad to worse.
….to give up completely their personal interests and take the plunge for the mother ?

Sentences from the given Phrases :

• We should be patriotic with all our heart.
• In every situation I shall be with you all in the mission.
• I am determined to rid this country of partiality and corruption.
• He has come into being in this country in every age.
• I am always reminded of my duties.
• People have collected from all parts of the country.
• To take a dip into Gangas’ water is so pleasing to the soul and mind.
• A true nationalist can never be selfish.
• If that be so, how can a lover of motherland sleep carelessly.
• I am not willing to go there unnecessarily.
• We should give up our personal interests in favour of national development.

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Bihar Board Solutions for Class 11 English aids you to prepare all the topics in it effectively. You need not worry about the accuracy of the Bihar Board Solutions for Class 11 Prose Chapter 10 Dolly at the Dentist Questions and Answers as they are given adhering to the latest exam pattern and syllabus guidelines. Enhance your subject knowledge by preparing from the Chapter wise Bihar Board Class 11th English Book Solutions and clarify your doubts on the corresponding topics.

Rainbow English Book Class 11 Solutions Chapter 10 Dolly at the Dentist

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Bihar Board Class 11 English Dolly at the Dentist Textual Questions and Answers

A . Work in small groups and discuss the following questions :

Question 1.
Have you ever suffered from toothach ? If yes, what did you do to overcome aching ?
Answer:
Students do it yourself.

Question 2.
Who curse you form toothache ?
Answer:
Students do it yourself.

Question 3.
Have you ever been to a dentist’s clinic or have you ever accompanied anvone to a dentist’s clinic ?
Answer:
Students do it yourself.

Question 4.
How did you feel at the clinic ?
Answer:
Students do it yourself.

B. Answer the following questions very briefly :

Question 1.
‘That was my first tooth.’ What does this mean ?
Answer:
The denntist means to say that it was the first tooth he took out in his private practice.

Question 2.
Why did the lady refuse to take gas ?
Answer:
The lady refused to take gas because it would have cost her five shillings extra. •

Question 3.
‘It’s your business to hurt people.’ Why does the lady say so ?
Answer:
The lady says so because a dentist takes out teeth and it hurts people.

Question 4.
Is the business of a dentist to hurt people ? Give your opinion.
Answer:
No, a dentist’s business is not to hurt people. It is to give relief from pain.

Question 5.
‘Is there anything else you would like to know ? ’ What made the dentist say so ?
Answer:
The doctor says so because he does not like her asking these questions. He wants her to leave.

Question 6.
Why did the lady ask the dentist to wear the five shilling piece on his watch chain ?
Answer:
She said So because it was the first five-shilling piece he had earned.

Question 7.
How long has the dentist been working in that clinic ?
Answer:
The dentist has been working in that clinic for six weeks.

Question 8.
Why is the dentist called a five -shilling dentist ?
Answer:
The dentist is called a five-shilling dentist because he charge five shillings for evervtihng.

Question 9.
When the lady asks the dentist if he has any family, he replies, ‘I am not married, What does family mean here ?
Answer:
Here family means wife and children.

Question 10.
What, in your opininon, does family stand for ? Does it mean only wife and children ?
Answer:
A family does not mean only wife and children. A family includes parents, brothers, sisters, grandparents, etc.

B. 2. Answer the following questions briefly :

Question 1.
What does the lady report to Philip about the dentist ?
Answer:
The lady tells Philip all the information she has had about the dentist she tells him that the dentist’s name is Valentine. He has been there for six. weeks. He is a bachelor. He does not own the house, nor the furniture. His professional plant is hired. She also adds that she and the dentist are great friends.

Question 2.
Why do Philip and Dolly invite Valentine to lunch ?
Answer:
They invite Valentine to lunch because they want to tell their mother that a respectable. Englishman has agreed to lunch with them. Their mother thinks that no Englishman will ever put up with them.

Question 3.
Is the dentist willing to dine with the lady and her brother ? Why ?
Answer:
No, the dentist is not willing to dine with them because they are perfect strangers for him.

Question 4.
What reasons do they give for their coming to England ?
Answer:
They say. that they came to England to get away from her mother’s work (books written by her). They are called the twentieth Century Treatises.

Question 5.
What are books called Twentieth Century Treatises ?
Answer:
The books called Twentieth century Treatises are:

• Twentieth Century Cooking
• Twentieth Century Creeds
• Twentieth Century Clothing
• Twentieth Century Conduct
• Twentieth Century Children

Question 6.
Why do they not want the dentist to read the books before they have bone ayay ?
Answer:
The books will improve the dentist’s mind but Philip and Dolly do not like people with Improved mind. So they want the dentist to read the books after they had gone.

C. 1. Long Answer Questions :

Question 1.
Write the gist of the conversation between Dolly and the Dentist.
Answer:
Dolly is a young lady. She visited a dentist to have her tooth taken out. The dentist took out her tooth and told her that it was his first tooth. Dolly appeared to be shocked because she felt that the dentist had started practising on her. But the dentist clarified that she was his first patient in his private practice.

Then the dentist asked her why she did not let him give her gas. She replied that she did not have gas because it would have cost her five shillings extra. The dentist was sorry that he had hurt her only because of five shillings. But she said that it was his job to hurt people.

Dolly looked about and began to ask him questions about his private life. The dentist told her that he had set up his clinic six weeks ago. The premises was on rent and the furniture belonged to the landlord. He had his professional equipment on hirepurchase system. He told her that he was a bachelor and his family did not live with him there.

She asked him why they called him a five-shilling dentist. He replied that they called him so because he charged five shillings for each thing.

Then Dolly gave the dentist a new five-shilling piece. She said it was his first fee. So he should drill a hole into it and wear it on his watch-chain.

Question 2.
What are the qualities you look for in a dentist ? Is Mr Valentine the dentist of your choice ? Explain.
Answer:
A dentist .should be well qualified, experienced and skilful. He should try to save the natural tooth as far as he can because there is no substitute for a natural tooth. If a tooth must be extracted, he should be able to do it quickly and causing as little pain to the patient as it is possible.

Mr Valentine is a dentist of my choice. He is considerate and skilful. He wanted to give Dolly gas so that she not feel pain. But she refused. When he learnt that she has refused because she did not want to spend another five shillings, he was sorry for her. He felt he had caused her pain which could be avoided. Dolly admires Valentine’s skill. Even though he extracted her tooth without gas, he did not cause much pain. He got it in one go. He must be a good dentist.

Question 3.
Find out the remarks or observations which you find particularly very amusing. Why do you find them amusing ?
Answer:
Dolly is a witty person. She is rather insolent. She makes humorous remarks. She says to the dentist that his business is to hurt people though she is miserly and did not have gas to save five shillings. She gives the dentist a new five-shilling piece and tells him to wear it as a medal because it is a great achievement to earn his first fee after having started his practice six weeks ago.

Dolly says that she is not the daughter of Mr Densmore Clandon. But Philip says that they could not be sure of it. It is an amusing situation that grown up chlidren do not know who their father is. Then they tell the dentist to read the books written by their mother because they will improve his mind.

But strangely they tell him to read the books when they are gone because they prefer people with unimproved minds.

Question 4.
Who do you find more amusing—Dolly or her brother ? Why ? Give reasons in favour of your choice.
Answer:
In find Dolly more amusing than her brother, Philip. Dolly’s dialogue with the dentist is amusing. Her remarks about the dentist’s work, and her questions about his personal life are queer. Then, at the height of it all, she gives him a crown and tells him to wear it like a medal because he earned his first fee after starting his practice six weeks ago.

Philip does not add spice to humour. Whatever he contributes, he does it with his sister. Hs only amusing remark is when he tells Dolly that she possibly does not know who their father is. Indeed Dolly is more amusing than Philip.

Question 5.
Give a brief character sketch of Dorothy Clandon using adjective from the list given below:

Answer:
Dorothy Clandon or Dolly is a young lady of eighteen. She is small and pretty. She is not an English woman. She is a native of Madeira. Naturally, she has a biscuit complexion. It is her first visit to England but her accent is perfectly British.Shc is a talktive woman, and appears to be impertinent and insolent. She asks the dentist questions about his business, his marital status, and his personal life, she is a miserly person.The dentist offers to give her gas so that she has no pain when he pulls out her tooth. But she is rather willing to bear pain than parting with another five shillings. She is very observant about the place and dentist’s equipment

C. 2. Group Discussion :
Discuss the following in groups or pairs:

Question a.
Nucleus family consists only of husband, wife and children. There is hardly andy room for uncle, aunt, grandpa or grandma in it. Do you think it is a better option than the joint family ? Give reasons in favour of your argument.
Answer:
I think a nucleus family is a better option. There are many reasons for it. In big cities, it is difficult to get accommodation for a large family. Besides, it is not possible to live in the same town or village any more. In olden days the whole joint family was engaged in a family occupation. This is no longer the case now. Of course, the nucleus family has to face some difficulties. But these difficulties are solved by creche and play-schools !

Joint family has more problems. There are quarrels between cousins, wives, brothers and mothers-in-law and daughters-in law. A nucleus family is a happy family. Young people like to lead an independent life without interference form elders.

Question b.
Being unnecessarily inquisitive about someone’s personal life is against social decorum. Do you agree ?
Answer:
There is no doubt that being unnecessarily inquisitive about someone’s personal life is against social decorum. Evervone has a right to lend an independent life. One has nothing to do with it unless it causes some trouble to others. One has a right to listen to music of one’s choice, eat what one likes, wear clothes as one pleases, keep long whiskers, wear a turban, hat or cap or nothing. It is his or her sweet will. But if one makes too moch noise, does something against social morality, or creates nuisance, then law can interfere.

C. 3. Composition :

Write a paragraph in about 100 words on the following :

Question a.
The duty of a doctor
Answer:
The duty of a doctor is to save a life, even if it is the life of a criminal. A doctor has his duty to his patient. Even if he has to forgo his own comfort, he is supposed to do his best to help his patient. Of course, a doctor is a human being and he has a right to a comfortable life. He needs money to satisfy the needs of his life. But a doctor should not be greedy. A doctor’s profession is very honourable, and a doctor should uphold the dignity of his profession at all costs.

Question b.
The relation between a doctor and a patient
Answer:
There is a relation of trust between a doctor and a patient. A patient is free to tell his/ her doctor about all his/her problems. A doctor is supposed to keep this information to himself, it is a bond of trust. It is something confidential. A doctor will not divulge this information to anybody. A doctor loves his patient and does all he can th help his patient. On the other hand, a patient has full faith in the skill and bonafide intentions of his/her doctor.

D. Word-study:

D. 1. Dictionary Use :

Ex -1. Correct the spelling of the following words:

Answer:

Ex-2. Look up a dictionary and write two meanings of each of the following words-the one in which it is used in the lesson and the other which is more common:
accent ,premises ,drill ,celebrated ,mounted
Answer:
Accent: (i) a way of pronouncing a language
(ii) a particular emphasis

premises : (i) the building and land occupied
(ii) a statement or idea that forms the basis for a theory

drill: (i) a tool or machine for boring holes
(ii) training in mlitary exercises

celebrated : (i) honour or praise publicly
(ii) perform (a cermony)

mounted : (i) to put in order
(ii) climbed up or on to

D. 2. Word-formation :

Look at the following examples: We’re from madieira, but perfectly respectable, so far.

May I ask whom I have the pleasure of entertainnig ?

Valentine, bewildered by the leaps and bounds with which their acquintanceship is proceeding, gasps.

You see that in the first example adjective respectable is denied form the verb respect. In the second example, present participle entertainin is derived from the verb entertain. In the last example, noun acquanitanceship is derived from the verb acqaint. In fact, a number of words can be derived from a verb as illustrated below.

Expert (v): expected (adj.) expectedly (adv) expectation (n) expectant (adj.) expectantly (adv.)

Ex. Write as many words derived from the following verbs as possible as illustrated above:

Answer:
acquaint (v): acquaintance (n), acquainted (adj.)
amuse (v): amusement (n), amused (adj.) amusingly (adv.), amusing (adj) celebrate (v): celebration (n), celebratory (adj.), celebated (adj.) celebrity (n).
continue (v): continual (adj.) continually (adv.) continuation (n), continued (adj.), continuing (adj.)
entertain (v) : entertainer (n), enteraining (adj.), entertainingly (adv), entertainment (n)
marry (v): marriage (n), marriageable (adj), married (adj.), marrying (adj.)
operate (v) : operating (adj.), operated (adj.), operatic (adj.), operation (n), operational (adj.), operationally (adv.), operator (n), operable (adj.) operatiction (adj).
resist (v): resistance (n), resistant (adj.), resister (n), resistible (adj.), resistive (adj.), resistivity (n)
produce (v): producing (adj.), produced (adj.), producer (n), product (n), production (n), productive (adj.), productively (adv.), productivity (n)
relate (v): relating (adj.), related (adj.), relatively (adv.)
practise (v): practising (adj.), practised (adj.), practitioner (n)

D. 3. Word-meaning :

Ex -1. Find from the lesson words the meanings of which have been- given on the left hand side. The last part of each word is given on the right hand side:
readiness to act ……………. tude
way of pronouncing ……………. cent
piece of furniture with shelves or drawers ……………. net
rest or sleep n the early ofternoon ……………. ta
the state of having lost ali hope ……………. pair
famous ……………. ted
laugh quietly with closed mouth ……………. kies
building together with its grounds ……………. mises
without trying to show respect ……………. antly
books that deal in detail with a single subject ……………. tises
Answer:
readiness to act – promptitude
way of pronouncing – accent
piece of furniture with shelves or drawers – cabinet
rest or sleep in the early afternoon – siesta
the state of having lost all hope – despair
famus – reputed
laugh quietly with closed mouth – chuckles
bulding together with its grounds – flippantly
without trying to show respect – premises

books that deal in detail with a single subject treatises

Ex-2. Fill in the Blanks with suitable Adjectives given below:
awful critical celebrated inquisitive
flippant mature momentary

1. She is ……………. enough to take her decision herself.
2. Dr. Bhabha was a ……………. scientist
3. It is difficult to forget that ……………. sight even today.
4. Chaitali’s ……………. expression makes her a very charming character.
5. After a ……………. hesitation, Philip entered the room.
6. Dr. Dwivedi has written a ……………. study of modem Hindi litera ture.
7. Any responsible man cannot make such a ……………. remark.

Answer:

1. mature
2. celebrated
3. awful
4. inqusitive
5. momentary
6. critical
7. flippant

D. 4. Phrases :

Ex-1. Read the lesson carefully and And out the sentences in which the following phrases have been used. used. Use them in sentences of your own:

Answer:
No, it’s all over.

Yes. I was going to ask whether your were by any chance a daughter of
Mr. Densmore Clandon of …………….. Hall.
PHILIP (Cutting her short); sh ! (valentine …………….. indiscretions).
The Young Lady (as if in capable of …………….. thing): Oh no.
…………….. he got my tooth out beautifully at the first go and ……………..
…………….. I had hurt you for the sake of five shillings.
…………….. a very pretty woman in miniature, hardly eighteen
A handsome man in miniature, obviously the ……………..
PHILIP; Been asking a lot o/questions ?
Thank you. (In spite of the biscuit-complexion she has not the slightest foreign accent).
…………….. bewildered by the leaps and bounds with which their acquain-tanceship is proceeding ……………..
…………….. (Looking about in search o/further conclusions) ……………..

Sentences with the use of above given Phrases:

He is known all over the world.
He is not my brother by any chance.
He strated his lecture cutting me short.
He behaves as if a mad.
He crossed the river at one go.
He sacrificed his life for the sake of the nation.
A beautiful woman in miniature appeared before me.
She asked me a lot of questions.
Inspite 0f illness, he appeared at the examination.
His wealth is going up by leaps and bounds.
The thirsty corw was moving in search 0/water.
I am not in the least tired.

E. Grammer :

Ex-Questions: Yes/No and information types:
Study the following questions from the lesson:
(a) Are they expensive ?
(b) Do you charge five shillings for everything ?
(c) Am I in time ?
You see that all the questions above begin with an auxiliary verb’ Are’, ‘Do’ or ‘Am’.

These questions are called Yes/No questions as they can be answered in ‘Yes’ or ‘No’ only.

You also see that the subject in example (b) is placed between the aux-iliary and the main verb. The structure of the Yes/No questions is further examplified in the following table :

Form ten Yes / No questions using each of the follwing auxiliaries twice: may, have, could, will, do.
Answer:
May I get your help ?
May I talk to your father ?
Have you taken your meal ?
Have you finished your task ?
Could I have a word with you ?
Could I speak to the Headmaster ?
Will you buy a car today ?
Will you do it at any cost ?
Do you know him ?
Do you like it ?

Ex-2. Study the following questions from the lesson:
(a) Why didn’t you let me give you gas ?
(b) How do you know your are not ?
(c) What difference does it make to
You see that all the questions in the examples begin with a wh-word, eg., ‘Why’ ‘and ‘What’.
These questions are called information questions as they ask for information of different kinds.
You can’t answer these questions by saying ‘yes’ or ‘no’, the pattern of these questions as given in the following table is : Wh-word + Yes/No questions.

Wh-word Auxiliary subject Main verb object, Complement, etc.

Now form eight more information questions using each of these Wh- words twic: Where, When, Why, How
Answer:
Where do you live ?
Where are you coming from ?
When did he go ?
When will he come ?
Why did you not inform me ?
Why did they oppose you ?
How can I inform you ?
How can I help you ?

Ex-3. Note how the Wh-words in the following questions are the subjects of the sentences and how they are followed directly by the main verb. Noauxiliary verb is used in these questions:

Now form six more Information questions using each of these wh- words twice: Who, What, Which
Answer:
Who is your lover ?
Who is the worker ?
What made you laugh ?
What made she cry ?
Which is the best policy ?
Which is the last point ?

F. Activity :

Taking help from reference books and your teacher find out:
(a) What is wit ?
(b) What is humour ?
Find out the instances of wit and humour in the lesson.
Answer:
(a) Wit: According to dictionary, the word stands for the capacity for inventive thought and quick understanding.

In the lesson we find such things with Dolly as she makes inquiries and comment expertly. For instance.

“The Dentist – It makes me feel as if I had hurt you for the sake of five shillings.”

“The young Lady – Well, so you have Why shouldn’t you ? It’s your business to hurt people.”

(b) Humour: The word stands for the quality in something that makes it funny or amusing.

In the less on we find humour from the beginning to the end. For example.

“The Dentist – That was my first tooth.
The young lady – (aghast): Your first! Do you mean to say you began practising on me ?
The dentist – Every dentist has to begin with somebody.
The younglady – Yes: Somebody in hospital, not people who pay.”

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Rainbow English Book Class 11 Solutions Chapter 9 National Unity, Nation and Nationality

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Bihar Board Class 11 English National Unity, Nation and Nationality Textual Questions and Answers

A. Work in small groups and discuss the following questions :

Question 1.
What type of country is India ?
Answer:
India is a vast country with diversity of climate, religions, faiths languages, lifestyle, etc. Still there is unity.

Question 2.
What is democracy ?
Answer:
Democracy means equal rights for all, and people have a right to choose their own government.

Question 3.
Name some famous personalities Bihar has produced.
Answer:
Bihar produced great man like Dr. Rajendra Prasad and Jayaprakash Narayan and many others.

Question 4.
Who was J.P. ? What do you know about him ?
Answer:
Lok Nayak Jayaprakash Narayan is popularly known as J.P. He was a great freedom fighter. He worked for Sarvodya.

Question 5.
How did he come to be known as ‘Lok Nayak’ ?
Answer:
He started a movement against suppression of civil liberties. It is called J.P. movement. He directed, the nation to true freedom. So he is known as Lok Nayak.

Question 6.
Why is 5th June known as ‘Sompoorna Kranti Diwas’ ?
Answer:
Students do you urself.

B. 1. Answer the following questions briefly :

Question 1.
What were the two important events and when did they take place ?
Answer:
The two important events took place in 1857 and 1885. In 1857. In 1857 it was an open and armed struggle for sovereign power, in 1885 it was a humble petitioning for a royal commission.

Question 2.
How did they bring incredible change in national outlook ?
Answer:
Both of these events were national movements. They created a sense of nationalism in India.

Question 3.
‘Nationalism does not mean the same thing to all the classes’. Why does J.P. say so ?
Answer:
J.P says so because according to him nationalism does nto comprise the interests of all the classes and groups in a nation.

Question 4.
What according to the author, is the first ‘breach’ in ‘national unity’ ?
Answer:
The first breach was, between the princes and the ‘national movement’. The national movement opposed the British Imperialism, but the princes supported it.

Question 5.
“No one with the least political understanding or experience can talk of unity with the landlords.” Why ? Explain.
Answer:
The landlords were the creation of British imperialism. They supported the British imperialism. They did not support national movement. But in case power was transferred into Indian hands, they wanted to ensure that their interests did not suffer on account of this.

Question 6.
What, according to J.P., is the second ‘breach’ in national unity ?
Answer:
The clash between die interests of big landlords and the ‘national movement’ is the second breach in national unity.

B. 2.1. Write T for True and F for False statement :

1. The Indian industrial class can effectively oppose imperialism.
2. The Indian industrial class support nationalism whole- heartedly.
3. The natives would love if the peasants became conscious of their ecomomic and polotical destiny.
4. A class-conscious working class means the break-up of national unity.

Answer:

1. (F)
2. (F)
3. (F)
4. (T)

B. 2.2. Answer the following questions briefly :

Question 1.
What is the third ‘breach’ in national unity.
Answer:
The vested interests of the industrial class are different form the objectives of national movement. It is the third breach

Question 2.
What do you understand by ‘ peasant raj’ ? Explain.
Answer:
Peasant raj means complete freedom from exploitation either by the natives or the foreigners. Rather, economic and political policies must safeguard the interests of the peasants.

Question 3.
‘National unity breaks-up as soon as the peasantry becomes conscious., What does J.P. mean by this statement ?
Answer:
If peasantry becomes conscious of their economic and political destiny, they will resole to direct action. It will be dangerous for both the foreigner as well as native oppressors. Then the national unity will break up.

C. 1. Long Answer Questions :

Question 1.
Attempt a definition of nationalism in the light of what J.P. says in the lesson.
Answer:
In common usage, nationalism means loyalty to one’s nation. It is equivalent to patriotism. It is a sentiment that binds all the people of nation by a common bond of common national interest. But J.P does not think that such a nationalism exists especially in context with India. In India there are many classes and groups. Their interests are devise. Even their interests clash with one another’s interests. The interests of the peasants are not the same as those of the landlords. The interests of workers are not the same as those of the industrialists.

J.P refers to two events of event of our national history, 1857 and 1885. The two event are looked upon as national movements, and the people who participated in them were nationalists. But the objectives of the two movements were entirely different and their objectives too were different. J.P. comes to the conclusion that nationalism means different things to different people, and the role is played at different times by different groups depending on the circumstances of history.

Question 2.
Which element does J.P. find sadly missing in the popular notion of nationalism ? How can it be incorporated ?
Answer:
J.P finds that there is no mass consciousness in the popular notion of nationalism. The workers and peasants, that constitute the masses, are ignored. They are exploited by industrialists and by landlords. Their direct Acton is looked upon as dangerous. In J.P.’s opinion simply freedom from imperialism will bring no freedom for the masses.

The upper or powerful classes will enjoy the fruit of workers’ and peasants’ fight against British imperialism, he wants freedom from exploitation. He wants peasant raj. By this he means that the peasants should have freedom to shape the nation’s economic and political policies in accordance with their own interests. The workers should be free from wage-slavery. He wants social ownership of means of production. But, unfortunately, the workers and peasants are not conscious of their political and economic destiny. No one even desires it, to keep on exploiting peasants and workers.

Question 3.
Did India really achieve what J.P. wanted it to achieve ?
Answer:
J.P. wanted freedom from exploitation for the peasants and workers. He was a socialist and wanted the workers to be free from wage-slavery. He wanted social ownership of means of production. No doubt his aims were idealistic. Perhaps that high level of freedom is not possible to achieve. In many countries this type of experiments have failed.

In India Nehru too wanted a socialistic pattern of society, But there are so many pulls and pushes. J.P has rightly remarked that India is made up of many groups and classes. The powerful classes, like industrialists, baboos and politicians are able to have their way. Still things have changed for workers and peasants. Big landlords have been abolished. Workers have rights. There are labour tribunals and courts. The workers and peasants are no longer cowed down. They are vote bank. Recently the government of India waived off their loans. But unless the fanners and peasants are free from hunger, unless they are educated; unless they are free from fear, their condition cannot change. J.P.’s dream is yet too distant to achieve.

C. 2. Group Discussion :

Discuss the following in groups or Pairs.

Question a.
True nationalism resides in mass-consciousness.
Answer:
Nationalism is not determined by geographical boundaries, religion or political affiliations alone. It resides in mass-consciousness. The jews were spread over many countries. They spoke different languages. But they had a consciousness of their oneness. So they all settled in Israel. The East Germany and West Germany were divided by a wall, they had different political systems.

But people in both the parts had a mass-consciousness of nationalism. They broke down the wall. East Pakistan and West Pakistan had no mass¬consciousness of the same nationalism. So East Pakistan broke away from West Pakistan. In India there was a mass-consciousness of nationalism. That was why people from all over India fought for only one aim-freedom from the British rule.

Question b.
Unity in Diversity
Answer:
India is a vast country . There is a variety of climates. People in different parts of the country speak many different languages. Their life styles, food, clothes are very different. But there is a sense of unity. This is the unity of an ancient culture and history. A sense of belonging to one nation. There is a unity in diversity. This sense of unity holds India together as one nation.

C. 3. Composition :

Question a.
You are the secretary of the cultural association of your school/ college, you have decided to hold a debate on ‘ have the objectives of sampoorna karanti’ really been achieved. Write a notice in about 50 words inviting students’ participation. Include time, vanue and topic of the debate. Also, mention the person to be contacted for the purpose.
Answer:
J.P Narayan Memorial School, Samastipur

NOTICE

5 th September 20…

Debate on Sampoorna Kranti

The Cultural Association of our school is holding a debate on
‘Have the’objective of Sampoorna Kranti been Achieved ? in the school auditorium on 15th September 20…
Students who desire to participate may contact the undersigned for details by 8th September.

Kaushal Kumar
Secretary

D. Word study:

D. 1. Dictionary Use :

Ex. 1. Correct the spelling of the following words:
Sovreign, cricumestances ,economicaly ,transffered ,strenth ,propgandi ,accordence ,bourgeosie ,ownership ,conscious
Answer:
Sovereign, circumstances, economically, propaganda, transferred strenght, accordance, bourgeoisie, ownership, conscious

Ex. 2. Look up a dictionary and write two meanings of each of the following words-the one in which it is used in the lesson and the other which is more common: strange, movement, play, interest, fight
Answer:
strange: (i) unusual (ii) peculiar
Movement: (i) agitation (ii) motion
play : (i) freedom of movement (ii) take part in games
Interest: (i) a subject about which one is concerned (ii) a person’s advantage
Fight : (i) take part in a violent struggle (ii) struggle to overcome or prevent.

D. 2. Word-Formation :

Look at the following examples:

“The result is the inability of this class to oppose imperialism. At least it can put pressure on it. But even this pressure is unable to exert as a class”. In the above example by adding ‘in’ to ‘ability’ and ‘an-‘ to ‘able’, we have formed the opposites ‘inability’ and ‘unable’ respectively. In the same way we can make opposite by adding ‘dis-‘ and ‘anti’ Given below is a list of selected words from the lesson. Make opposite by adding ‘in-‘, ‘un-‘ ‘dis-‘ and ‘anti-‘ whether suitable:

real educated national economic complete:
do interested controlled secure satisfied
Answer:
real – unreal
do – undo
educated – uneducated
interested – disinterested
national – anti national
controlled – uncontrolled
economic – uneconomic
secure – insecure
complete – incomplete
satisfied – unsatisfied

Ex. 2. Fill in the blanks with suitable words given below:
mysterious, motherland, moment, majority, imperialism, industrialist, withdraw, objective, freedom, development

(a) India is our
(b) Every ………. of our life is important. .
(c) Rural ………. is a must for any country
(d) J.P. had the support of ……….
(e) In moden times ………. has changed its old form
(f) We should honour and gurd our ……….
(g) What is main ………. of learning English ?
(h) There is something ……….. about Netaji’s death.
(i) Jamshedji Tata was a great ……….
(j) The troops began to ………. from Kargil.
Answer:
a motherland
b. moment
c. development
d.majority
e. imperialism
f. freedom
g. objective
h. mysterious
i. industrialist
j. with draw, imperialism

E. Grammar :

Ex. 1. Fill in the blanks with correct prepositions :

1. Nationalism means different things ………. different times.
2. These facts throw a good light ………. the problem of nationalism.
3. The baboos did not stand ………. all the classes.
4.The difference lies ………. its objective.
5. The purpose was to stampede the people ………. voting for the perpetuation ………. British capitalism.
Answer:
1. at
2. on
3. for
4. in
5. into, of.

Ex. 2. Read the following examples:

“Thus, we see first that the Indian industrialists are unable themselves ‘to oppose’ imperialism”

In the above line an infinitiv ‘to oppose’ has been used. Find as many instances of infinitives as you can from the lesson and use them in sentences of your own.
Answer:
(i) Nationalism to them mean complete freedom ‘to exploit’ the country’s resources (of men and materials) and ‘to build’ up their fortunes.
(ii) To do’ this they require a great deal of control over the state.
(iii) The result is the inability of this class ‘to oppose’ imperialism.
(iv) But even this pressure it is unable ‘to exert’ as a class.
(v) The purpose in reality was ‘to stampede’ the people into voting for the perpetuation of British capitalism.

Sentences: to do-I was not willing ‘to do’ so.
to oppose – There was none ‘to oppose’ him..
to exert – Now I have no capacity ‘to exert’.
to stampede – They were forced by the contestant ‘to stampede’ in the election.
to exploit – It is not fair ‘to exploit others.
to build – The purpose of the education is ‘to build’ up our character.

F. Activity :

Ex. 1. Make a note of the important points in paragraph 1-6
Ex. 2. Write summary based on your notes in about 150 words. Give a suitable title to your write-up.
Answer:
Ex. 1. Notes
1.1. National unity nation nationalism
1.2. Struggle for sovereignty
1.3. India’s demands
2.1. National movement
2.2. Two events-difference
2.3. Baboos-peasants
3.1. Unity-personal interests
3.2. Comic of unity
3.3. Undefined Swaraj
4.1. Cricumstances
4.2. to stampede into voting
4.3. Perpetuation of British capitalism.

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Bihar Board Class 12 Chemistry Solutions Chapter 6 तत्त्वों के निष्कर्षण के सिद्धान्त एवं प्रक्रम Textbook Questions and Answers, Additional Important Questions, Notes.

BSEB Bihar Board Class 12 Chemistry Solutions Chapter 6 तत्त्वों के निष्कर्षण के सिद्धान्त एवं प्रक्रम

Bihar Board Class 12 Chemistry तत्त्वों के निष्कर्षण के सिद्धान्त एवं प्रक्रम Text Book Questions and Answers

पाठ्यनिहित प्रश्न एवं उनके उत्तर

प्रश्न 6.1
पाठ्यपुस्तक की सारणी 6.1 में दर्शाए गए अयस्कों में से कौन-से चुम्बकीय पृथक्करण विधि द्वारा सान्द्रित किए जा सकते हैं?
उत्तर:
यदि अयस्क या गैंग (दोनों में से एक) चुम्बकीय हो उन्हें चुम्बकीय प्रथक्करण विधि द्वारा किया जा सकता है। सारणी में दर्शाए गये अयस्क जैसे-हेमेटाइट (Fe₂O₃), मेग्नेटाइट (Fe₃O₄) सिडेराइट (FeCO₃) तथा आयरन पाइराइट (FeS₂) को चुम्बकीय पृथक्करण विधि द्वारा सान्द्रित किया जा सकता है।

प्रश्न 6.2
ऐलुमिनियम के निष्कर्षण में निक्षालन का क्या महत्त्व है?
उत्तर:
ऐलुमिनियम के मुख्य अयस्क बाक्साइट में मुख्यत: SiO₂, आयरन ऑक्साइड आदि की अशुद्धियाँ होती हैं जिन्हें ऐलुमिनियम के निष्कर्षण में निक्षालन द्वारा हटाया जा सकता है तथा शुद्ध ऐलुमिना भी प्राप्त किया जा सकता है।

प्रश्न 6.3
अभिक्रिया Cr₂O₃ + 2Al → Al₂O₃ + 2Cr (∆G° = – 421 kJ) के गिब्ज ऊर्जा मान से लगता है कि अभिक्रिया ऊष्मागतिकी के अनुसार सम्भव है, पर यह कक्ष ताप पर सम्पन्न क्यों नहीं होती?
उत्तर:
चूँकि संक्रियण ऊर्जा की निश्चित मात्रा ऊष्मा गतिकीय अभिक्रियाओं के लिए आवश्यक होती है, अतः दी गई अभिक्रिया को सम्पन्न करने के लिए अतिरिक्त ऊष्मा की आवश्यकता होती है।

प्रश्न 6.4
क्या यह सत्य है कि कुछ विशिष्ट परिस्थितियों में मैग्नीशियम, Al₂O₃ को अपचित कर सकता है और Al, Mgo को? वे परिस्थितियाँ कौन-सी है?
उत्तर:
अध्यापक की सहायता से करें।

Bihar Board Class 12 Chemistry तत्त्वों के निष्कर्षण के सिद्धान्त एवं प्रक्रम Additional Important Questions and Answers

अभ्यास के प्रश्न एवं उनके उत्तर

प्रश्न 6.1
कॉपर का निष्कर्षण हाइड्रोधातुकर्म द्वारा किया जाता है, परन्तु जिंक का नहीं। व्याख्या कीजिए।
उत्तर:
जिंक का मानक इलेक्ट्रोड विभव (E^Θ) [Zn²⁺ | Zn = – 0.76 V] कॉपर व E^Θ | Cu²⁺ | Cu = + 0.34] से कम होता है। दूसरी ओर जिंक Cu²⁺ आयनों के विलयन से Cu को विस्थापित कर सकता है।
Zn (s) + Cu²⁺ (aq) → Zn²⁺ (aq) + Cu (s)
इसीलिए Zn²⁺ आयनों के विलयन से जिंक विस्थापित करने के लिए हमें इससे अधिक क्रियाशील धातु की आवश्यकता होगी अर्थात्

परन्तु ये सभी धातुएँ जल से क्रिया करके अपने सम्बन्धित आयन बनाती हैं तथा H₂ गैस मुक्त करती है। इसलिए Al, Mg आदि को Zn²⁺ आयनों के विलयन से जिंक विस्थापित करने में प्रयुक्त नहीं किया जा सकता। अतः कॉपर का निष्कर्षण हाइड्रोधातुकर्म द्वारा किया जा सकता है, परन्तु जिंक का नहीं।

प्रश्न 6.2
फेन प्लवन विधि में अवनमक की क्या भूमिका है?
उत्तर:
फेन प्लावन विधि में, अवनमक की भूमिका दो सल्फाइड अयस्कों को पृथक् करना होता है। उदाहरणार्थ: एक अयस्क में से जिंक सल्फाइड (ZnS) तथा लेड सल्फाइड को पृथक करने के लिए सोडियम साइनाइड (NaCN) प्रयुक्त किया जाता है। इस चयन से ZnS को फेन में आने से रोकता है परन्तु Pbs को फेन में आने देता है। अत: ZnS अयस्क से पृथक किया जा सकता है।

प्रश्न 6.3
अपचयन द्वारा आक्साइड अयस्कों की अपेक्षा पाइराइट से ताँबे का निष्कर्षण अधिक कठिन क्यों है?
उत्तर:
Cu₂S के निर्माण की मानक मुक्त ऊर्जा (∆_fG^Θ); CS₂ तथा H₂S की मानक मुक्त ऊर्जा की तुलना में अधिक होती है। इसलिए कार्बन तथा हाइड्रोजन Cu₂S को Cu में अपचयित नहीं कर सकते हैं।
Cu₂S + H₂ → 2Cu ↓+ H₂S ↑
2Cu₂S + C → 4Cu ↓+ CS₂
दूसरी ओर Cu₂O का ∆_fG^Θ CO₂ की तुलना में अत्यन्त कम होता है, इसलिए कार्बन सरलता से Cu₂O को Cu में अपचयित कर सकता है।
Cu₂O(s) + C(s) → 2Cu(s) + CO(g)
इसी कारण अपचयन द्वारा ऑक्साइड अयस्कों की अपेक्षा पाइराइट से ताँबे का निष्कर्षण अधिक कठिन है।

प्रश्न 6.4
व्याख्या कीजिए –

1. मण्डल परिष्करण
2. स्तम्भ वर्णलेखिकी।

उत्तर:
1. मण्डल परिष्करण (Zone Refining):
यह विधि इस सिद्धान्त पर आधारित है कि अशुद्धियों की विलेयता धातु की ठोस अवस्था की अपेक्षा गलित अवस्था में अधिक होती है। अशुद्ध धातु की छड़ के एक किनारे पर एक वृत्ताकार गतिशील तापक लगा रहता है (चित्र)।

इसकी सहायता अशुद्ध धातु को गर्म किया जाता है। तापक जैसे ही आगे की ओर बढ़ता है, गलित से शुद्ध धातु क्रिस्टलित हो जाती है तथा अशुद्धियाँ संलग्न गलित मण्डल में चली जाती हैं।

चित्र – मण्डल परिष्करण प्रक्रम

इस क्रिया को कई बार दोहराया जाता है तथा तापक को एक ही दिशा में बार-बार चलाते हैं। अशुद्धियाँ छड़ के एक किनारे पर एकत्रित हो जाती हैं। इसे काटकर अलग कर लिया जाता है। यह विधि मुख्य रूप से अतिउच्च शुद्धता वाले अर्धचालकों तथा अन्य अतिशुद्ध धातुओं; जैसे-जर्मेनियम, सिलिकॉन, बोरॉन, गैलियम तथा इंडियम को प्राप्त करने के लिए बहुत उपयोगी है।

2. स्तम्भ वर्णलेखिकी (Column Chromatography):
यह विधि इस सिद्धान्त पर आधारित है कि अधिशोषक पर मिश्रण के विभिन्न घटकों का अधिशोषण अलग-अलग होता है। मिश्रण को द्रव या गैसीय माध्यम में रखा जाता है जो कि अधिशोषक में से गुजरता है। स्तम्भ में विभिन्न घटक भिन्न-भिन्न स्तरों पर अधिशोषित हो जाते हैं। बाद में अधिशोषित घटक उपर्युक्त विलायकों (निक्षालक) द्वारा निक्षालित कर लिए जाते हैं। गतिशील माध्यम की भौतिक

अवस्था, अधिशोषक पदार्थ की प्रकृति एवं गतिशील माध्यम के गमन के प्रक्रम पर भी निर्भर होने के कारण इसे ‘स्तम्भ वर्णलेखिकी’ नाम दिया जाता है। इस प्रकार की एक विधि में कांच की नली में Al₂O₃ का एक स्तम्भ बनाया जाता है तथा गतिशील माध्यम जिसमें अवयवों का विलयन उपस्थित होता है, द्रव प्रावस्था में होता है।

यह स्तम्भ-वर्णलेखिकी का एक उदाहरण है। यह सूक्ष्म मात्रा में पाए जाने वाले शुद्धिकरण और शुद्ध किए जाने वाले तत्व तथा अशुद्धियों के रासायनिक गुणों में अधिक भिन्नता न होने की स्थिति में, शुद्धिकरण के लिए अत्यधिक उपयोगी होती है। स्तम्भ वर्णलेखिकी में प्रयुक्त प्रक्रम में चित्र में दर्शाया गया है।

चित्र-स्तम्भ वर्णलेखिकी

प्रश्न 6.5
673 K ताप पर C तथा CO में से कौन-सा अच्छा अपचायक है?
उत्तर:
जब कार्बन डाइआक्सीजन से अभिक्रिया करता है, तब दो अभिक्रियाँ सम्भव होती हैं –
C(s) + O₂ (g) → CO₂ (g)
2C(s) + O₂ (g) → 2CO (g) प्रथम अभिक्रिया में उत्पन्न CO₂ का आयतन, प्रयुक्त O₂ के आयतन के बराबर होता है, इसलिए ∆S अत्यन्त कम होता है तथा ∆G ताप के साथ परिवर्तित नहीं होता है। अतः ∆G तथा T के मध्य ग्राफ लगभग क्षैतिज होता है। द्वितीय अभिक्रिया प्रयुक्त O₂ के प्रत्येक एक आयतन के लिए CO के दो आयतन उत्पन्न करती है।

चित्र-कार्बन के लिए एर्लिंघम आरेख

अतः ∆S धनात्मक होता है तथा ∆G ताप बढ़ाने पर ऋणात्मक रूप से बढ़ता है। परिणामस्वरूप एलिंघम आरेख पर इसकी रेखा का ढाल नीचे की ओर होता है। अभिक्रियाओं C → CO₂ तथा C → CO के लिए दोनों रेखाएँ 983 K पर एक-दूसरे को काटती हैं।

इस ताप से नीचे CO₂ का निर्माण करने वाली अभिक्रिया ऊष्मीय रूप से अधिक सम्भव होगी, परन्तु 673 K से अधिक ताप पर CO का निर्माण होगा। दूसरे शब्दों में 673 K से नीचे ताप पर C तथा CO दोनों अपचायक की भाँति कार्य करते हैं ‘क्योंकि CO का CO₂ में आक्सीकरण C → CO₂ की अपेक्षा सरलता से हो सकता है, इसलिए 673 K से ताप पर CO कार्बन की अपेक्षा अधिक प्रभावी अपचायक होता है।

प्रश्न 6.6
कॉपर के विद्युत-अपघट्न शोधन में ऐनोड पंक में उपस्थित सामान्य तत्वों के नाम दीजिए। वे वहाँ कैसे उपस्थित होते हैं?
उत्तर:
कॉपर के विद्युत अपघट्न शोधन में ऐनोड पंक में उपस्थित सामान्य तत्व ऐन्टीमनी, सेलेनियम, सिल्वर, गोल्ड आदि (CuSO₄ + H₂SO₄) हैं। ये तत्व, कम क्रियाशील होते हैं जिससे ये विलयन द्वारा प्रभावित नहीं होते और ऐनोड पर ऐनोड पंक के रूप में विद्यमान रहते हैं।

प्रश्न 6.7
आयरन (लोहे) के निष्कर्षण के दौरान वात्या भट्टी के विभिन्न क्षेत्रों में होने वाली अभिक्रियाओं को लिखिए।
उत्तर:
वात्या भट्टी मे विभिन्न ताप-परासों में आयरन ऑक्साइड का अपचयन होता है। वात्या भट्टी में होने वाली अभिक्रियाएँ निम्नलिखित हैं –
500 – 800K पर (वात्या भट्टी में निम्न ताप परिसर में)
3Fe₂O₃ + CO → 2Fe₃O₄ + CO₂↑
Fe₃O₄ + 4CO → 3Fe ↓+ 4CO₂ ↑
Fe₂O₃ + CO → 2FeO + CO₂ ↑
900 – 1500K पर (वात्या भट्टी में उच्च ताप-परिसर में)
C + CO₂ → 2CO ↑
FeO + CO → Fe ↓+ CO₂ ↑
चूना पत्थर (लाइमस्टोन) भी CaO में अपघटित हो जाता है जो अयस्क की सिलिकेट अशुद्धि को धातुमल के रूप में हटा देता है। धातुमल स्लैग गलित अवस्था में हो जाता है तथा आयरन से पृथक्कृत हो जाता है।

प्रश्न 6.8
जिंक ब्लेण्ड से जिंक के निष्कर्षण में होने वाली रासायनिक अभिक्रियाओं को लिखिए।
उत्तर:
जिंक ब्लेण्ड से जिंक के निष्कर्षण में होने वाली रासायनिक अभिक्रियाएँ निम्नलिखित हैं –

1. सान्द्रण (Concentration):
अयस्क का सान्द्रण फेन प्लावन प्रक्रम द्वारा किया जाता है।

2. भर्जन (Roasting):
सान्द्रित अयस्क को लगभग 1200K ताप पर वायु की अधिकता में भर्जन किया जाता है जिससे जिंक ऑक्साइड प्राप्त होता है।

3. अपचयन (Reduction):
प्राप्त जिंक ऑक्साइड को चूर्णित कोक के साथ मिलाकर एक फायर क्ले रिटॉर्ट में 1673K तक गर्म करने पर जिंक धातु में अपचयित हो जाता है।

4. विद्यत-अपघटनी शोधन (Electrolytic refining):
अशुद्ध जिंक ऐनोड तथा कैथोड शुद्ध जिंक कैथोड लेते हैं। इसमें विद्युत-अपघट्य तनु H₂SO₄ से अम्लीकृत ZnSO₄ विलयन लेकर विद्युत धारा प्रवाहित करने पर शुद्ध Zn कैथोड पर प्राप्त हो जाता है।

प्रश्न 6.9
कॉपर के धातुकर्म में सिलिका की भूमिका बताइए।
उत्तर:
भर्जन के दौरान, कॉपर पाइराइट FeO तथा Cu₂O के मिश्रण में परिवर्तित हो जाते हैं।

2FeS + 3O₂ → 2FeO + 2SO₂
FeO तथा कॉपर, कॉपर मेट के रूप में प्राप्त होता है इसमें Cu₂S तथा Fes होते हैं। FeO, SiO₂ से संयोग करके फेरस सिलिकेट (FeSiO₃) धातुमल बनाता है जो गलित अवस्था में मैट पर तैरता है।

प्रश्न 6.10
‘वर्णलेखिकी’ पद का क्या अर्थ है?
उत्तर:
वर्णलेखिकी (Chromatography) को मूल रूप में ग्रीक शब्द Chroma अर्थात् रंग या वर्ण तथा graphy अर्थात् लेखन है। किसी मिश्रण के कुछ या सभी अवयवों को भिन्न प्रावस्थाओं में पृथक करने के प्रक्रम को वर्णलेखिकी कहते हैं। यह विधि किसी मिश्रण के अवयवों के दो प्रावस्थाओं के मध्य वर्णात्मक वितरण पर आधारित है। इस में एक अवस्था स्थिर अवस्था ठोस या द्रव होती है और दूसरी प्रावस्था गतिमान प्रावस्था द्रव या गैस होती है।

प्रश्न 6.11
वर्णलेखिकी में स्थिर प्रावस्था के चयन में क्या मापदण्ड अपनाए जाते हैं?
उत्तर:
स्थिर प्रावस्था का चयन के लिए अशुद्धियाँ स्थिर प्रावस्था में शुद्ध होने वाले तत्व से अधिक विलेय हो। जब स्तम्भ का निष्कर्षण किया जाता है, तब अशुद्धियाँ स्थिर प्रावस्था द्वारा रुक जाती है तथा शुद्ध घटक को सरलतापूर्वक हटा देते हैं।

प्रश्न 6.12
निकिल-शोधन की विधि समझाइए।
उत्तर:
निकिल शोधन की मॉन्ड प्रक्रम:
इस प्रक्रम में निकिल को कार्बन मोनोक्साइड के प्रवाह में गरम करने से वाष्पसील निकिल टेट्राकार्बोनिल संकुल बन जाता है –

इस कार्बोनिल को और अधिक ताप पर गरम करते हैं, जिससे यह विघटित होकर शुद्ध धातु दे देता है।

प्रश्न 6.13
सिलिकायुक्त बॉक्साइट अयस्क में से सिलिका को ऐलुमिना से कैसे अलग करते हैं? यदि कोई समीकरण हो तो दीजिए।
उत्तर:
सिलिकायुक्त बॉक्साइट अयस्क को NaOH के सान्द्रविलयन के साथ 473 – 523K ताप पर तथा 35-36 bar दाब पर गर्म करते हैं। इससे, ऐलुमिना, सोडियम ऐलुमिनेट के रूप में तथा सिलिका, सोडियम सिलिकेट के रूप में घुल जाती है तथा अशुद्धियाँ अवशेष के रूप में रह जाती हैं।

सोडियम सिलिकेट परिणामी विलयन को छानकर अविलेय अशुद्धियों (यदि कोई हो) को हटा दिया जाता है तथा इसे CO₂ गैस प्रवाहित करके उदासीन कर दिया जाता है। इस अवस्था पर विलयन को ताजा बने हुए जलयोजित Al₂O₃ के नमूने से बीजरोपित किया जाता है, जो अवक्षेपण को प्रेरित करता है।

सोडियम सिलिकेट विलयन में शेष रह जाता है तथा जलयोजित ऐलुमिना को छानकर, सुखाकर तथा गर्म करके पुनः शुद्ध Al₂O₃ प्राप्त कर लिया जाता है।

प्रश्न 6.14
उदाहरण देते हुए भर्जन एवं निस्तापन में अन्तर बताइए।
उत्तर:
निस्तापन (Calcination):
इस क्रिया में सांद्रित अयस्क को इतना गर्म करते हैं कि वह पिघले नहीं। इस क्रिया में अयस्क से गैसीय पदार्थ अथवा वाष्पशील पदार्थ अलग हो जाते हैं। गैस निकलने से अयस्क सरन्ध्र हो जाते हैं।
कार्बोनेट अयस्क अपघटित हो आक्साइड में बदल जाते हैं तथा CO₂ निकल जाती है।
CaCO₃ + CaO + CO₂
ZnCO₃ → ZnO + CO₂

भर्जन (Roasting):
इस क्रिया में अयस्क को वायु की उपस्थिति में उसके गलनांक से नीचे गर्म किया जाता है। भर्जन क्रिया के द्वारा अयस्क आंशिक या पूर्ण रूप से आक्सीकृत हो जाता है। यहाँ S, As आदि अशुद्धियाँ ऑक्साइड के रूप में निकल जाती हैं तथा अयस्क ऑक्साइड में परिवर्तित हो जाते हैं। जैसे-जिंक ब्लैड (ZnS) के भर्जन पर ZnO प्राप्त होता है।
2ZnS + 3O₂ → 2ZnO + 2SO₂

भर्जन एवं निस्तापन में अन्तर (Difference between Roasting and Calcination):
निस्तापन तथा भर्जन लगभग समान क्रियाएँ होती हैं। भर्जन में अयस्क को अकेले अथवा किसी अन्य पदार्थ के साथ गर्म करते हैं, जबकि निस्तापन अयस्क को अकेले ही गर्म करते हैं। भर्जन में As, Sb, S आदि की अशुद्धियाँ आक्साइड बनकर बाहर निकल जाती हैं, जबकि निस्तापन में H₂O तथा CO₂ आदि बाहर निकल जाते हैं।

प्रश्न 6.15
ढलवाँ लोहा कच्चे लोहे से किस प्रकार भिन्न होता है?
उत्तर:
वात्या भट्टी से प्राप्त लोहे में लगभग 4% कार्बन तथा अन्य अशुद्धियाँ; जैसे – S, P, Si, Mn सूक्ष्म मात्रा में उपस्थित रहती है। यह कच्चे लोहे (pig iron) के नाम से जाना जाता है तथा विभिन्न आकृतियों में ढाला जा सकता है। ढलवाँ लोहा (cast iron) कच्चे लोहे से भिन्न होता है तथा इसे कच्चे लोहे को, रद्दी लोहे एवं कोक के साथ गर्म हवा के झोंकों द्वारा पिघलाकर बनाया जाता है। इसमें थोड़ा कम कार्बन (लगभग 3%) होता है तथा यह अति कठोर और भंगुर होता है।

प्रश्न 6.16
अयस्कों तथा खनिजों में अन्तर स्पष्ट कीजिए।
उत्तर:
खनिज (minerals):
प्रकृति में पाए जाने वाले धातु के विभिन्न खनिज कहलाते हैं, जैसे – एक सॉल्ट (NaCl)

अयस्क (Ores):
वे खनिज जिसे शद्ध धातु का निष्कर्षण अधिक मात्रा में कम व्यय पर सुविधा से किया जा सकता है, अयस्क कहलाते हैं। जैसे – बॉक्साइट (Al₂O₃.2H₂O) एल्युमीनियम का अयस्क है। अतः सभी अयस्क खनिज होते हैं, परन्तु सभी खनिज अयस्क नहीं होते हैं।

प्रश्न 6.17
कॉपर मैट को सिलिका की परत चढ़े हुए परिवर्तकों में क्यों रखा जाता है?
उत्तर:
कॉपर मैट में Cu₂S तथा FeS से जब कॉपर मैट को सिलिका की परत चढ़े हुए परिवर्तक में लेकर इसमें गर्म वायु का तेज झोंका प्रवाहित करते हैं तब मैट में उपस्थित FeS फेरिक ऑक्साइड ऑक्सीकृत हो जाता है और सिलिका से क्रिया कर FeSiO₂ धातुमल बनाता है।

जब धातुमल (FeSiO₃) को अलग कर लिया जाता है तो Cu₂S ऑक्सीकृत होकर Cu₂O बनाता है जो Cu₂S के संयोग से कॉपर धातु देता है।
2Cu₂S + 3O₂ → 2Cu₂O + 2SO₂
2Cu₂O + Cu₂S → 6Cu + SO₂
अतः कॉपर के निष्कर्षण में सिलिका की भूमिका धातुमल को हटाने की होती है।

प्रश्न 6.18
ऐलुमिनियम के धातुकर्म में क्रायोलाइट की क्या भूमिका है?
उत्तर:
यह ऐलुमिना के गलनांक को कम करता है और उसकी विद्युत चालकता को बढ़ाता है।

प्रश्न 6.19
निम्न कोटि के कॉपर अयस्कों के लिए निक्षालन क्रिया को कैसे किया जाता है?
उत्तर:
निम्न कोटि के कॉपर अयस्कों से कॉपर का निष्कर्षण हाइड्रोधातु कर्म द्वारा करते हैं। इसे अम्ल या जीवाणु के उपयोग से निक्षालित करते हैं तथा Cu²⁺ आयन युक्त विलयन H₂ से क्रिया करते हैं।
Cu²⁺ (aq) + H₂ (g) → Cu(s) + 2H⁺ (aq)

प्रश्न 6.20
CO के उपयोग करते हुए अपचयन द्वारा जिंक ऑक्साइड से जिंक का निष्कर्षण क्यों नहीं किया जाता?
उत्तर:
चूंकि CO से CO₂ के निर्माण की मानक मुक्त ऊर्जा (∆_fG^Θ), Zn से Zn0 के निर्माण की मानक ऊर्जा अधिक होने के कारण Zno को Zn में अपचयित करने के लिए CO का उपयोग नहीं किया जा सकता है।

प्रश्न 6.21
Cr₂O₃ के विरचन के लिए ∆_fG^Θ का मान – 540 kJ mol^-1 है तथा Al₂O₃ के लिए – 827 kJ mol^-1 है। क्या Cr₂O₃ का अपचयन Al से सम्भव है?
गणना:
इस प्रक्रम में अभिक्रियाओं के दो समीकरण है –

समीकरण (1) को (2) में से घटाने पर,
\(\frac{4}{3}\) cr(s) – \(\frac{4}{3}\) Al(s) → \(\frac{2}{3}\) Cr₂O₃ (s) – \(\frac{2}{3}\) Al₂O₃(s);
\(\frac{4}{3}\) Al (s) + \(\frac{2}{3}\) Cr₂O₃ (s) → \(\frac{2}{3}\) Al₂O₃ (s) + \(\frac{4}{3}\) Cr (s); ∆_fG^Θ = -287 kJ mol^-1
∵ संयुक्त रेडॉक्स अभिक्रिया का ∆_fG^Θ ऋणात्मक है।
∴ Cr₂O₃ का अपचयन Al से सम्भव है।

प्रश्न 6.22
C व CO में से Zno के लिए कौन-सा अपचायक अच्छा है?
उत्तर:
जिंक ऑक्साइड का अपचयन कोक द्वारा किया जाता है। इसमें कॉपर की स्थिति की अपेक्षा ताप अधिक रखा जाता है। तापन के लिए ऑक्साइड की कोक तथा मृदा के साथ छोटी-छोटी ईटें बनाई जाती हैं।

धातु को आसवित कर तथा तीव्र शीतलन द्वारा एकत्र कर लेते हैं। C से CO के निर्माण की मुक्त ऊर्जा (∆_fG^Θ) 1120K से अधिक ताप पर कम हो जाती है, जबकि O से CO₂ के निर्माण की मुक्त ऊर्जा, Zn0 के AG° की तुलना में, 1323 K से अधिक ताप पर कम हो 1120 K से अधिक ताप पर C से CO के बनने में मुक्त ऊर्जा कम हो जाती है।

जबकि 1323 K से अधिक ताप पर C से CO₂ के बनने में मुक्त ऊर्जा, ZnO की मुक्त ऊर्जा की तुलना में कम हो जाती है। चूंकि CO से CO₂ की मुक्त ऊर्जा ZnO से अधिक होती है, अत: C, ZnO का Zn में अपचयन कर सकता है जबकि CO नहीं। अत: c व CO में से ZnO के लिए अच्छा अपचायक C है, जबकि CO नहीं।

प्रश्न 6.23
किसी विशेष स्थिति में अपचायक का चयन ऊष्मागतिकी कारकों पर आधारित है। आप इस कथन से कहाँ तक सहमत हैं? अपने मत के समर्थन में दो उदाहरण दीजिए।
उत्तर:
किसी निश्चित धात्विक ऑक्साइड का धात्विक अवस्था में अपचयन करने के लिए उचित अपचायक का चयन करने में ऊष्मागतिकी कारक सहायता करता है। इसे निम्नवत् समझा जा सकता है –

ऐलिंघम आरेख से यह स्पष्ट होता है कि वे धातुएँ, जिनके लिए उनके ऑक्साइडों के निर्माण की मानक ऊर्जा अधिक ऋणात्मक होती है, उन धातु ऑक्साइडों को अपचयित कर सकती है जिनके लिए उनके सम्बन्धित ऑक्साइडों के निर्माण की मानक मुक्त ऊर्जा कम ऋणात्मक होती है। दूसरे शब्दों में कोई धातु किसी धातु के ऑक्साइड को केवल तब अपचयित कर सकती है, जबकि यह एलिंघम आरेख में इस धातु से नीचे स्थित हो।

चूँकि संयुक्त रेडॉक्स अभिक्रिया का मानक मुक्त ऊर्जा परिवर्तन ऋणात्मक होगा (जोकि दोनों धातु आक्साइडों के ∆_fG^Θ में अन्तर के तुल्य होता है।); अत: Al तथा Zn दोनों FeO को Fe में अपचयित कर सकते हैं, परन्तु Fe, Al₂O₃, को Al में तथा ZnO को Zn में अपचयित नहीं कर सकता। इसी प्रकार C, ZNO को Zn में अपचयित कर सकता है, परन्तु CO को नहीं।

प्रश्न 6.24
उस विधि का नाम लिखिए जिसमें क्लोरीन सहउत्पाद के रूप में प्राप्त होती है। क्या होगा यदि NaCl के जलीय विलयन का विद्युत अपघटन किया जाए?
उत्तर:
सोडियम धातु डॉउन प्रक्रम द्वारा प्राप्त की जा सकती है। इस प्रक्रम में NaCl तथा CaCl₂ के संगलित मिश्रण का 873K पर विद्युत अपघटन किया जाता है। जिससे सोडियम कैथोड पर निरावेशित होती है तथा Cl₂ ऐनोड पर सहउत्पाद के रूपं में होती है।

यदि NaCl के जलीय विलयन का विद्युत अपघटन किया जाता है तो कैथोड पर H₂ मुक्त होती है तथा Cl₂ ऐनोड पर प्राप्त होती है। चूँकि Na⁺/ Na रेडॉक्स युग्म का E°(= – 2.17 V) जल के E° (= – 0.83 V) की अपेक्षा कम होता है तथा अत: जल Na⁺ आयनों की अपेक्षा H₂ में अपचयित हो जाता है।

प्रश्न 6.25
ऐलुमिनियम के विद्युत-धातुकर्म में ग्रेफाइट छड़ की क्या भूमिका है?
उत्तर:
इस धातु में Al₂O₃ में Na₃AlF₆ या CaF₂ मिलाया जाता है जिससे मिश्रण का कम हो जाता है और इसमें चालकता आ जाती है। विद्युत-अपघटन में ग्रेफाइट के रूप में विद्युत अपघटन तथा स्टील कैथोड के रूप में प्रयुक्त होते हैं। विद्युत-अपघट्य में Al कैथोड पर और CO तथा CO₂ ऐनोड पर बनती है।

कथोड:
Al³⁺ (गलित) → Al(l)

ऐनोड:
C(s) + O^2-(गलित) → CO(g) + 2e^–
C(s) + 2O^2- (गलित) → CO₂(g) + 4e^–
ग्रेफाइट के स्थान पर किसी अन्य धातु लेने पर मुक्त ऑक्सीजन न केवल इलेक्ट्रोड की धातु को ऑक्सीकृत करेगी बल्कि कैथोड पर मुक्त Al की कुछ मात्रा को Al₂O₃ में परिवर्तित कर देगी। अत: Al के निष्कर्षण में ग्रेफाइट की भूमि का ऐनोड पर 0, को संरक्षित करके मुक्त होने वाले Al की कुछ मात्रा को पुन: Al₂O₃ में परिवर्तन न करने में रोकना होती है।

प्रश्न 6.26
निम्नलिखित विधियों द्वारा धातुओं के शोधन के सिद्धान्तों की रूपरेखा दीजिए:

1. मण्डल परिष्करण
2. विद्युतअपघट्न परिष्करण
3. वाष्य प्रावस्था परिष्करण

उत्तर:
1. मण्डल परिष्करण:

मण्डल परिष्करण (Zone Refining):
यह विधि इस सिद्धान्त पर आधारित है कि अशुद्धियों की विलेयता धातु की ठोस अवस्था की अपेक्षा गलित अवस्था में अधिक होती है। अशुद्ध धातु की छड़ के एक किनारे पर एक वृत्ताकार गतिशील तापक लगा रहता है (चित्र)।

इसकी सहायता अशुद्ध धातु को गर्म किया जाता है। तापक जैसे ही आगे की ओर बढ़ता है, गलित से शुद्ध धातु क्रिस्टलित हो जाती है तथा अशुद्धियाँ संलग्न गलित मण्डल में चली जाती हैं।

चित्र – मण्डल परिष्करण प्रक्रम

इस क्रिया को कई बार दोहराया जाता है तथा तापक को एक ही दिशा में बार-बार चलाते हैं। अशुद्धियाँ छड़ के एक किनारे पर एकत्रित हो जाती हैं। इसे काटकर अलग कर लिया जाता है। यह विधि मुख्य रूप से अतिउच्च शुद्धता वाले अर्धचालकों तथा अन्य अतिशुद्ध धातुओं; जैसे-जर्मेनियम, सिलिकॉन, बोरॉन, गैलियम तथा इंडियम को प्राप्त करने के लिए बहुत उपयोगी है।

2. विधुतअपघटन परिष्करण:
इस विधि में अशुद्ध धातु की ऐनोड बनाते हैं। उसी धातु की शुद्ध धातु-पट्टी को कैथोड के रूप में प्रयुक्त करते हैं। इन्हें एक उपयुक्त विद्युतअपघटनी विश्लेषित्र में रखते हैं जिसमें उसी धातु का लवण घुला रहता है। अधिक क्षारकीय धातु विलयन में रहती है तथा कम क्षारकीय धातुएँ ऐनोड पंक (anode mud) में चली जाती हैं। इस प्रक्रम की व्याख्या, विद्युत विभव की धारण, अधिविभव तथा गिब्ज के द्वारा (उपयोग) भी की जा सकती है। ये अभिक्रियाएँ निम्नलिखित हैं –

ऐनोड: Mn → Mn⁺ + ne^–
कैथोड: Cu²⁺ + 2e^– → Cu
फफोलेदार कॉपर से अशुद्धियाँ ऐनोड पंक के रूप में जमा होती हैं, जिसमें एण्टिमनी सेलीनियम टेल्यूरियम, चाँदी, सोना तथा प्लैटिनम मुख्य होती हैं। इन तत्वों की पुनः प्राप्ति से शोधन की लागत की क्षतिपूर्ति हो सकती है। जिंक का शोधन भी इसी प्रकार से किया जा सकता है।

3. वाष्प प्रावस्था परिष्करण-इस विधि में, धातु को वाष्पशील यौगिक में परिवर्तित किया जाता है तथा दूसरे स्थल पर एकत्र कर लेते हैं। इसके बाद इसे विघटित करके शुद्ध धातु प्राप्त कर लेते हैं। इस प्रक्रिया की दो आवश्यकताएँ होती हैं –

(क) उपलब्ध अभिकर्मक के साथ धातु वाष्पशील यौगिक बनाती हो तथा
(ख) वाष्पशील पदार्थ आसानी से विघटित हो सकता हो, जिससे धातु आसानी से पुनः प्राप्त की जा सके।

उदाहरणार्थ:
जर्कोनियम या टाइटेनियम शोधन के लिए वॉन-आरकैल विधि – यह Zr तथा Ti जैसी कुछ धातुओं से अशुद्धियों की तरह उपस्थित सम्पूर्ण ऑक्सीजन तथा नाइट्रोजन को हटाने में बहुत उपयोगी है। परिष्कृत धातु को निर्वातित पात्र में आयोडीन के साथ गर्म करते हैं। धातु आयोडाइड अधिक सहसंयोजी होने के कारण वाष्पीकृत हो जाता है।
Zr + 2I₂ → ZrI₄

धातु आयोडाइड को विद्युत धारा द्वारा 1800K ताप पर गर्म किए गए टंगस्टन तन्तु पर विघटित किया जाता है। इस प्रकार से शुद्ध धातु तन्तु पर जमा हो जाती है।
ZrI₄ → Zr + 2I₂ ↑

प्रश्न 6.27
उन परिस्थितियों का अनुमान लगाइए जिनमें Al, MgO को अपचयित कर सकता है।
उत्तर:
इसके लिए रासायनिक अभिक्रियाएँ निम्नवत् हैं –
\(\frac{4}{3}\) Al + O₂ → \(\frac{2}{3}\) Al₂O₃; ∆_fG^Θ Al, Al₂O₃ ……………….. (1)
2 Mg + O₂ → 2MgO; ∆_fG^Θ Mg, MgO ………………. (2)
एलिंघम आरेख द्वारा स्पष्टीकरण:
कुछ ऑक्साइडों के विरचन में T तथा ∆G^Θ के एलिंघम आरेख निम्न प्रकार से हैं –

कुछ ऑक्साइडों के विरचन में गिब्ज ऊर्जा ∆G^Θ तथा ताप T के मध्य वक्र (आरेखीय एलिंघम आलेख)।
उपर्युक्त आरेख से 1665K से नीचे तापमान पर Al₂O₃ का ∆_fG^Θ मान MgO की अपेक्षा कम ऋणात्मक है। अतः जब समीकरण (1) को समीकरण (2) में से घटाने पर संयुक्त रेडॉक्स अभिक्रियाओं ∆_fG^Θ ऋणात्मक होता है। 2Mg + \(\frac{2}{3}\) Al₂O₃ → 2MgO + \(\frac{4}{3}\)Al
∆_fG^Θ = ऋणात्मक …………….. (3)
अतः 1665K से नीचे तापमान पर Mg Al₂O₃ को Al में अपचयित कर सकता है। 1665K से अधिक तापमान पर Al₂O₃ का मान MgO की तुलना में अधिक ऋणात्मक होता है। अत: जब समीकरण (2) को समीकरण (1) में से घटाने पर संयुक्त रेडॉक्स अभिक्रिया अर्थात् समीकरण (4) का ∆_fG^Θ ऋणात्मक होता है।
\(\frac{4}{3}\) Al + 2MgO → \(\frac{2}{3}\) Al₂O₃ + 2Mg;
∆_fG^Θ = ऋणात्मक ……………………. (4)
अतः 1665K से अधिक तापमान पर Al MgO को Mg में अपचयित कर सकता है।

Bihar Board Class 12 Chemistry Solutions Chapter 9 उपसहसंयोजन यौगिकTextbook Questions and Answers, Additional Important Questions, Notes.

BSEB Bihar Board Class 12 Chemistry Solutions Chapter 9 उपसहसंयोजन यौगिक

Bihar Board Class 12 Chemistry उपसहसंयोजन यौगिक Text Book Questions and Answers

पाठ्यनिहित प्रश्न एवं उनके उत्तर

प्रश्न 9.1
निम्नलिखित उपसहसंयोजन यौगिकों के सूत्र लिखिए:

1. टेट्राऐम्मीनडाइऐक्वाकोबाल्ट (III) क्लोराइड
2. पोटैशियम टेट्रासायनोनिकिलेट (II)
3. ट्रिस (एथेन – 1, 2 – डाइऐमीन) क्रोमियम (III) क्लोराइड
4. ऐम्मीनब्रोमिडोक्लोरिडोनाइट्रिटो – N – प्लैटिनेट (II)
5. डाइक्लोरोबिस (एथेन – 1, 2 – डाइऐमीन) प्लैटिनम (IV) नाइट्रेट
6. आयरन (III) हेक्सासायनोफेरेट (II)

उत्तर:

1. [Co(NH₃)₄(H₂O)₂]Cl₃
2. K₂[Ni(CN)₄]
3. [Cr(en)₃]Cl₃
4. [Pt(NH₃) BrCl(NO₂)]^–
5. [PtCl₂(en)₂] (NO₃)₂
6. Fe₄[Fe(CN)₆]₃

प्रश्न 9.2
निम्नलिखित उपसहसंयोजन यौगिकों के IUPAC नाम लिखिए –

1. [Co(NH₃)₆]Cl₃
2. [Co(NH₃)₅Cl]Cl₂
3. K₃[Fe(CN)₆]
4. K₃[Fe(C₂O₄)₃]
5. K₂[PaCl₄]
6. [Pt(NH₃)₂ CI(NH₂CH₃)]Cl

उत्तर:

1. हेक्साऐम्मीनकोबाल्ट (III) क्लोराइड
2. पेन्टाऐम्मीनक्लोरिडोकोबाल्ट (III) क्लोसइड
3. पोटैशियम हेक्सासायनोफेरेट (III)
4. पोटैशियम ट्राइऑक्सेलेटोफेरेट (III)
5. पोटैशियम टेट्राक्लोरिडोपैलेडेट (II)
6. डाइऐम्मीनक्लोरिडो (मेथिलऐमीन) प्लैटिनम (II) क्लोराइड।

प्रश्न 9.3
निम्नलिखित संकुलों द्वारा प्रदर्शित समावयवता का प्रकार बतलाइए तथा इन समावयवों की संरचनाएँ बनाइए:

1. K[Cr(H₂O)₂ (C₂O₄)₂]
2. [Co(en)₃] Cl₃
3. [Co(NH₃)₅(NO₂)](NO₃)₂
4. [Pt(NH₃)(H₂O)Cl₂]

उत्तर:
(i) (क) सिस के लिए ज्यामितीय (सिस – ट्रान्स) तथा प्रकाशिक समावयव हो सकते हैं –

(ख) सिस के प्रकाशिक समावयव (d- तथा l-)

(ii) दो प्रकाशिक समावयव हो सकते हैं।

(iii) आयनन समावयव:
दस समावयव सम्भव हैं (ज्यामितीय, आयनन तथा बन्धनी समावयव सम्भव हैं)।
[Co(NH₃)₅(NO₂)](NO₃)₂, [Co(NH₃)₅(NO₃)] (NO₂)(NO₃)

बन्धनी समावयव:
[Co(NH₃)₅(NO₂)] (NO₃)₂, [Co(NH₃)₅ (ONO)] (NO₃)₂

(iv) ज्यामितीय समावयव (सिस-, ट्रान्स-) हो सकते हैं।

प्रश्न 9.4
इसका प्रमाण दीजिए कि [Co(NH₃)₅Cl] SO₄ तथा [Co(NH₃)₅SO₄]Cl आयनन समावयव हैं।
उत्तर:
आयनन समावयव जल में घुलकर भिन्न आयन देते हैं, इसलिए विभिन्न अभिकर्मकों से भिन्न – भिन्न अभिक्रियाएँ करते हैं।
[Co(NH₃₅Cl)SO₄ + Ba²⁺ → BaSO₄(s)
[Co(NH₃)₅SO₄] + Ba²⁺ → कोई अभिक्रिया नहीं
[Co(NH₃)₅Cl]SO₄ + Ag⁺ → कोई अभिक्रिया नहीं
[Co(NH₃)SO₄]Cl + Ag⁺ → AgCl(s)

प्रश्न 9.5
संयोजकता आबन्ध सिद्धान्त के आधार पर समझाइए कि वर्ग समतलीय संरचना वाला [Ni(CN)₄]^2- आयन प्रतिचुम्बकीय है तथा चतुष्फलकीय ज्यामिति वाला [NiC₄]^2- आयन अनुचुम्बकीय है।
उत्तर:
[Ni(CN)₄]^2- का चुम्बकीय व्यवहार (Magnetic behaviour of [Ni(CN)₄]^2-: Ni का परमाणु क्रमांक 28 है। Ni, Ni²⁺ तथा [Ni(CN)₄]^2- में निकिल की अवस्था के इलेक्ट्रॉनिक विन्यास निम्नलिखित हैं:

संकरण संकुल आयन [Ni(CN)₄]^2- प्रतिचुम्बकीय है, चूंकि इसमें अयुगलित इलेक्ट्रॉन नहीं होते हैं।

[NiCl₄]^2- का चुम्बकीय व्यवहार (Magnetic behaviour of [NiCl₄^2-): इसमें Cl^– दुर्बल क्षेत्र लिगेण्ड है तथा यह इलेक्ट्रॉनों का युग्मन नहीं करता है।

संकुल आयन Co[NiCl₄]^2- में इसके d – उपकोश में अयुगलित इलेक्ट्रॉन होते हैं, इसलिए यह अनुचुम्बकीय होता है।

प्रश्न 9.6
[NiCl₄]^2- अनुचुम्बकीय है, जबकि [Ni(CO)₄] प्रतिचुम्बकीय है यद्यपि दोनों चतुष्फलकीय हैं।
उत्तर:
[Ni(CO)₄] में निकिल शून्य ऑक्सीकरण अवस्था में है, जबकि [NiCl₄]^2- में यह +2 ऑक्सीकरण अवस्था में है। Co लिगेण्ड की उपस्थिति में निकिल के अयुगलित d – इलेक्ट्रॉन युगलित हो जाते हैं, परन्तु Cl^– दुर्बल लिगेण्ड होने के कारण अयुगलित इलेक्ट्रॉनों को युगलित करने योग्य नहीं होता है। चूँकि [Ni(CO)₄] में कोई अयुगमित इलेक्ट्रॉन नहीं है, अतः यह प्रतिचुम्बकीय है और [NiCl₄]^2- में अयुगमित इलेक्ट्रॉनों की उपस्थिति के कारण यह अनुचुम्बकीय होता है।

प्रश्न 9.7
[Fe(H₂O₆)]³⁺ प्रबल अनुचुम्बकीय है, जबकि [Fe(CN)₆]^3- दुर्बल अनुचुम्बकीय। समझाइए।
उत्तर:
CN^– (एक प्रबल लिगेण्ड) की उपस्थिति में, 3d – इलेक्ट्रॉन युगलित होकर केवल एक अयुगलित इलेक्ट्रॉन छोड़ते हैं। d²sp³ संकरण आन्तरिक कक्षक संकुल बनाता है, इसलिए [Fe(CN)₆]^3- दुर्बल अनुचुम्बकीय होता है। H₂O (एक दुर्बल लिगेण्ड) की उपस्थिति में 3d – इलेक्ट्रॉन युगलित नहीं होते। संकरण sp³d² है जो बाह्य कक्षक संकुल, जिसमें पाँच अयुगलित इलेक्ट्रॉन होते हैं, बनाता है, इसलिए [Fe(H₂O)₆]³⁺ प्रबल अनुचुम्बकीय होता है।

प्रश्न 9.8
समझाइए कि [Co(NH₃)₆]³⁺ एक आन्तरिक कक्षक संकुल है, जबकि [Ni(NH₃)₆]^2- एक बाह्य कक्षक संकुल है।
उत्तर:
NH₃ की उपस्थिति में 3d – इलेक्ट्रॉन युग्मित होकर दो रिक्त d – कक्षक छोड़ते हैं जो [Co(NH₃)₆]²⁺ की स्थिति में आन्तरिक कक्षक संकुल बनाने वाले d²sp³ संकरण में सम्मिलित होते हैं।

Ni(NH₃)₆]²⁺ में निकिल +2 ऑक्सीकरण अवस्था में है तथा इसका d⁸ विन्यास है। इसमें बाह्य कक्षक संकुल बनाने वाला sp³d² संकरण सम्मिलित होता है।

प्रश्न 9.9
वर्ग समतली [Pt(CN)₄]^2- आयन में अयुगलित इलेक्ट्रॉन की संख्या बतलाइए।
उत्तर:
तत्व ₇₈Pt वर्ग 10 में स्थित है तथा इसका इलेक्ट्रॉनिक विन्यास 5d⁹ 6s¹ है। अत: Pt²⁺ का विन्यास d⁸ है।

वर्ग समतली संरचना के लिए संकरण dsp² होता है। चूँकि 5d में अयुगलित इलेक्ट्रॉन युगलित होकर रिक्त dsp² कक्षक संकरण के लिए एक रिक्त कर देते हैं अतः इसमें अयुगलित इलेक्ट्रॉन नहीं है।

प्रश्न 9.10
क्रिस्टल क्षेत्र सिद्धान्त को प्रयुक्त करते हुए समझाइए कि कैसे हेक्साऐक्वा मैंगनीज (II) आयन में पाँच अयुगलित इलेक्ट्रॉन हैं, जबकि हेक्सासायनो आयन में केवल एक ही अयुगलित इलेक्ट्रॉन है।
उत्तर:
उत्तर-ऑक्सीकरण अवस्था +2 में Mn का विन्यास 3d⁵ होता है। लिगण्ड के रूप में H₂O की उपस्थिति में इन पाँच इलेक्ट्रॉनों का वितरण \(t_{2 g}^{3} e_{g}^{2}\) होते हैं अर्थात् उच्च प्रचक्रण संकुल के कारण सभी इलेक्ट्रॉन अयुगलित रह जाते हैं। लिगेण्ड के रूप में CN^– की उपस्थिति में इन इलेक्ट्रॉन का वितरण \(t_{2 g}^{5} e_{g}^{0}\) है अर्थात् दो t_2g कक्षकों में युगलित इलेक्ट्रॉन है, जबकि तीसरे t_2g कक्षक में एक अयुगलित इलेक्ट्रॉन होता है।

प्रश्न 9.11
[Cu(NH₃)₄]²⁺ संकुल आयन के β₄ का मान 2.1 × 10¹³ है, इस संकुलन के समग्र वियोजन स्थिरांक के मान की गणना कीजिए।
गणना:
समग्र वियोजन स्थिरांक, समग्र स्थायित्व स्थिरांक का व्युत्क्रम होता है।

= 4.7 × 10^-14

Bihar Board Class 12 Chemistry उपसहसंयोजन यौगिक Additional Important Questions and Answers

अभ्यास के प्रश्न एवं उनके उत्तर

प्रश्न 9.1
वर्नर की अभिधारणाओं के आधार पर उपसहसंयोजन यौगिकों में आबन्धन को समझाइए।
उत्तर:
उपसहसंयोजन यौगिकों में आबन्धन को समझाने के लिए वर्नर ने सन् 1898 में उपसहसंयोजन यौगिकों का सिद्धान्त प्रस्तुत किया। इस सिद्धान्त की मुख्य अभिधारणाएँ निम्नलिखित हैं:

1. उपसहसंयोजन यौगिकों में धातुएँ दो प्रकार की संयोजकताएँ दर्शाती हैं प्राथमिक तथा द्वितीयक।

2. प्राथमिक संयोजकताएँ सामान्य रूप से धातु परमाणु की ऑक्सीकरण अवस्था से सम्बन्धित होती हैं तथा आयननीय होती हैं। ये संयोजकताएँ ऋणात्मक आयनों द्वारा सन्तुष्ट होती हैं।

3. द्वितीयक संयोजकताएँ धातु परमाणु की उपसहसंयोजन संख्या से सम्बन्धित होती हैं। द्वितीयक संयोकजताएँ अनआयननीय होती हैं। ये उदासीन अणुओं अथवा ऋणात्मक आयनों द्वारा सन्तुष्ट होती हैं। द्वितीयक संयोजकता उपसहसंयोजन संख्या के बराबर होती है तथा इसका मान किसी धातु के लिए सामान्यत: निश्चित होता है।

4. धातु से द्वितीयक संयोजकता से आबन्धित आयन समूह विभिन्न उपसहसंयोजन संख्या के अनुरूप दिक्स्थान में विशिष्ट रूप से व्यवस्थित रहते हैं। आधुनिक सूत्रीकरण में इस प्रकार की दिक्स्थान व्यवस्थाओं को समन्वय बहुफलक (coordination polyhedra) कहते हैं। गुरुकोष्ठक में लिखी स्पीशीज संकुल तथा गुरुकोष्ठक के बाहर लिखे आयन प्रति आयन (counter ions) कहलाते हैं।

उन्होंने यह भी अभिधारणा दी कि संक्रमण तत्वों के समन्वय यौगिकों में सामान्यतः अष्टफलकीय, चतुष्फलकीय व वर्ग समतली ज्यामितियाँ पाई जाती हैं। इस प्रकार [Co(NH₃)₆]³⁺, [CoCl(NH₃)₅]²⁺ तथा [CoCl₂(NH₃)₄]⁺ की ज्यामितियाँ अष्टफलकीय हैं, जबकि [Ni(CO)₄] तथा [PtCl₄]^2- क्रमशः चतुष्फलकीय तथा वर्ग समतली हैं।

उपर्युक्त अभिधारणाओं से वर्नर, जिसने निम्नलिखित यौगिको को कोबाल्ट (III) क्लोराइड की NH₃ से अभिक्रिया करके बनाया, ने इन यौगिकों (उपसहसंयोजक) की संरचना की सफलतापूर्वक व्याख्या की जिसका वर्णन निम्नलिखित है –

CoCl₃.6NH₃ नारंगी
CoCl₃.5NH₃.H₂O गुलाबी
CoCl₃.5NH₃ बैंगनी CoCl₃.3NH₃ हरा
CoCl₃.4NH₃ के विभिन्न रंगों का कारण यह है कि ये समपक्ष तथा विपक्ष समावयव होते हैं।

– प्राथमिक संयोजकता या ऑक्सीकरण अवस्था
– द्वितीयक संयोजकता या उपसहसंयोजन संख्या

प्रश्न 9.2
FeSO₄ विलयन तथा (NH₄)2SO₄ विलयन का 1:1 मोलर अनुपात में मिश्रण Fe²⁺ आयन का परीक्षण देता है, परन्तु CuSO₄ व जलीय अमोनिया का 1:4 मोलर अनुपात में मिश्रण Cu²⁺ आयनों का परीक्षण नहीं देता। समझाइए क्यों?
उत्तर:
FeSO₄ विलयन तथा (NH₄)₂SO₄ विलयन का 1:1 मोलर अनुपात में मिश्रण द्विक लवण –

जो विलयन में आयनित होकर Fe²⁺ आयन देता है। अतः यह Fe²⁺ आयनों का परीक्षण देता है। CuSO₄ व जलीय विलयन का 1:4 मोलर अनुपात में मिश्रण संकर लवण [Cu(NH₃)₄] SO₄ बनाता है। संकुल आयन, [Cu(NH₃)₄]²⁺ आयनित होकर Cu²⁺ आयन नहीं देता है। अतः यह Cu²⁺ आयन के परीक्षण नहीं देता।

प्रश्न 9.3
प्रत्येक के दो उदाहरण देते हुए निम्नलिखित को समझाइए समन्वय समूह, लिगेण्ड, उपसहसंयोजन संख्या, उपसहसंयोजन बहुफलक, होमोलेप्टिक तथा हेटेरोलेप्टिक।
उत्तर:
1. उपसहसंयोजन सत्ता या समन्वय समूह:
केन्द्रीय धातु परमाणु अथवा आयन से किसी एक निश्चित संख्या में आबन्धित आयन. अथवा अणु मिलकर एक उपसहसंयोजन सत्ता का निर्माण करते हैं। उदाहरणार्थ: [CoCl₃(NH₃)₃] एक उपसहसंयोजन सत्ता है जिसमें कोबाल्ट आयन तीन अमोनिया अणुओं तथा तीन क्लोराइड आयनों से घिरा है। अन्य उदाहरण हैं –
[Ni(CO)₄], [PtCl₂(NH₃)₂], [Fe(CN₆]^4-, [Co(NH₃)₆]³⁺ आदि।

2. लिगेण्ड:
उपसहसंयोजन सत्ता में केन्द्रीय परमाणु/आयन से परिबद्ध आयन अथवा अणु लिगेण्ड कहलाते हैं। ये सामान्य आयन हो सकते हैं; जैसे – Cl^– छोटे अणु हो सकते हैं; जैसे – H₂O या NH₃, बड़े अणु हो सकते हैं;
H₂NCH₂CH₂NH₂N(CH₂CH₂NH₂)₃ वृहदाणु भी हो सकते हैं; जैसे-प्रोटीन।

3. उपसहसंयोजन संख्या:
एक संकुल में धातु आयन की उपसहसंयोजन संख्या (CN) उससे आबन्धित लिगण्डों के उन दाता परमाणुओं की संख्या के बराबर होती है जो सीधे धातु आयन से जुड़े हों।

उदाहरणार्थ:
संकुल आयनों [PtCl₆]^2- तथा [Ni(NH₃)₄]²⁺ में Pt तथा Ni की उपसहसंयोजन संख्या क्रमश: 6 तथा 4 हैं। इसी प्रकार संकुल आयनों [Fe(C₂O₄)₃]^3- और [Co(en)3] + में Fe और Co दोनों की समन्वय संख्या 6 हैं; क्योंकि \(\mathrm{C}_{2} \mathrm{O}_{4}^{2-}\) तथा en (एथेन-1, 2-डाइऐमीन) द्विदन्तुर लिगेण्ड हैं।

उपसहसंयोजन संख्या के सन्दर्भ में यह तथ्य महत्वपूर्ण है कि केन्द्रीय परमाणु/आयन की उपसहसंयोजन संख्या केन्द्रीय परमाणुःआयन तथा लिगेण्ड के मध्य बने केवल (σ) (सिग्मा) आबन्धों की संख्या के आधार पर ही निर्धारित की जाती है। यदि लिगेण्ड तथा केन्द्रीय परमाणु/आयन के मध्य π (पाई) आबन्ध बने हों तो उन्हें नहीं गिना जाता।

4. उपसहसंयोजन बहुफलक:
केन्द्रीय परमाणु/ आयन से सीधे जुड़े लिगेण्ड परमाणुओं की दिक्स्थान व्यवस्था (special arrangement) को उपसहसंयोजन बहुफलक कहते हैं।

चित्र – विभिन्न उपसहसंयोजन बहुफलकों की आकृतियाँ – M केन्द्रीय परमाणु/आयन को तथा L एकदन्तुर

लिगेण्ड को प्रदर्शित करता है इनमें अष्टफलकीय, वर्ग समतलीय तथा चतुष्फलकीय मुख्य हैं। उदाहरणार्थ: [Co(NH₃)₆]³⁺ अष्टफलकीय है, [Ni(CO)₄] चतुष्फलकीय है तथा [PtCl₄]^2- वर्ग समतलीय है। चित्र में विभिन्न उपसहसंयोजन बहुफलकों की आकृतियाँ दर्शाई गई हैं।

5. होमोलेप्टिक:
संकुल जिनमें धातु परमाणु केवल एक प्रकार के दाता समूह से जुड़ा रहता है, होमोलेप्टिक संकुल कहलाते हैं।
उदाहरणार्थ: [Co(NH₃)₆]³⁺ तथा [Fe(CN)₆]²⁺

6. हेटरोलेप्टिक:
संकुल जिनमें धातु परमाणु एक से अधिक प्रकार के दाता समूहों से जुड़ा रहता है, हेटरोलेप्टिक संकुल कहलाते हैं। उदाहरणार्थ – [Co(NH₃)₄Cl₂]⁺ तथा [Pt(NH₃)₅Cl]³⁺

प्रश्न 9.4
एकदन्तुर, द्विदन्तुर तथा उभयदन्तुर लिगेण्ड से क्या तात्पर्य है? प्रत्येक के दो उदाहरण दीजिए।
उत्तर:
जब एक लिगेण्ड धातु आयन से एक दाता परमाणु द्वारा परिबद्ध होता है; जैसे – Cl^– H₂O या NH₃ तो लिगेण्ड एकदन्तुर (unidentate) कहलाता है। जब लिगेण्ड दो दाता परमाणुओं द्वारा परिबद्ध हो सकता है; जैसे – H₂NCH₂CH₂NH₂ (एथेन-1, 2-डाइऐमीन) अथवा C₂O^2-₄ (ऑक्सेलेट) तो ऐसा लिगेण्ड द्विदन्तुर कहलाता है।

वह लिगेण्ड जो दो भिन्न परमाणुओं द्वारा जुड़ सकता है, उसे उभयदन्ती संलग्नी या उभयदनी लिगेण्ड कहते हैं। ऐसे लिगेण्ड के उदाहरण हैं – NO^–₂, तथा SCN^– आयन। NO^–₂ आयन केन्द्रीय धातु परमाणु/आयन से या तो नाइट्रोजन द्वारा अथवा ऑक्सीजन द्वारा संयोजित हो सकता है। इसी प्रकार SCN^– आयन सल्फर अथवा नाइट्रोजन परमाणु द्वारा संयोजित हो सकता है।

प्रश्न 9.5
निम्नलिखित उपसहसंयोजन सत्ता में धातुओं के ऑक्सीकरण संख्या का उल्लेख कीजिए –

1. [Co(H₂O)(CN)(en)₂]²⁺
2. [CoBr₂(en)₂]⁺
3. [PtCl₄]^2-
4. K₃[Fe(CN₆)]
5. [Cr(NH₃)₃Cl₃]

गणना:

प्रश्न 9.6
IUPAC नियमों के आधार पर निम्नलिखित के लिए सूत्र लिखिए –

1. टेट्राहाइड्रोऑक्सोजिंकेट (II)
2. पोटैशियम टेट्राक्लोरिडोपैलेडेट (II)
3. डाइऐम्मीनडाइक्लोरिडोप्लैटिनम (II)
4. पोटैशियम टेट्रासायनोनिकिलेट (II)
5. पेन्टोऐम्मीननाइट्रिटो-0-कोबाल्ट (III)
6. हेक्साऐम्मीनकोबाल्ट (III)) सल्फेट
7. पोटैशियम ट्राइ (ऑक्सेलेटो) क्रोमेट (III)
8. हेक्साऐम्मीनप्लैटिनम (IV)
9. टेट्राबोमिडोक्यूप्रेट (II)
10. पेन्टाऐम्मीननाइट्रिटो-N-कोबाल्ट (III)

उत्तर:

1. [Zn(OH)₄]^2-
2. K₂[PdCl₄]
3. [Pt(NH₃))₂Cl₂]
4. K₂[Ni(CN)₄]
5. [Co(NH₃)₅(ONO)²⁺
6. [Co(NH₃)₆]₂ (SO₄)₃
7. K₃[Cr(C₂O₄)₃]
8. [Pt(NH₃)₆]⁴⁺
9. [CuBr₄]^2-
10. [Co(NH₃)₅ (NO₂)]²⁺

प्रश्न 9.7
IUPAC नियमों के आधार पर निम्नलिखित के सुव्यवस्थित नाम लिखिए:

1. [Co(NH₃)₆]Cl₃
2. [Pt(NH₃)₂ Cl(NH₂CH₃)]Cl
3. [Ti(H₂O)₆]³⁺
4. [Co(NH₃)₄ Cl(NO₂)]Cl
5. [Mn(H₂O)₆]²⁺
6. [NiCl₄]^2-
7. [Ni(NH₃)₆]Cl₂
8. [Co(en)₃]³⁺
9. [Ni(CO)₄]

उत्तर:

1. हेक्साऐमीनकोबाल्ट (III) क्लोराइड
2. डाइऐमीनक्लोरिडो (मेथिलऐमीन) प्लैटिनम (II)क्लोराइड
3. हेक्साऐक्वाटाइटेनियम (III) आयन
4. टेट्राऐमीनक्लोरिडोनाइट्रिटो – N – कोबाल्ट (III) क्लोराइड
5. हेक्साऐक्वामैंगनीज (II) आयन
6. टेट्राक्लोरिडोनिकिलेट (II) आयन
7. हेक्साऐमीनिकिल (II) क्लोराइड
8. ट्रिस (एथेन-1, 2-डाइऐमीन) कोबाल्ट (III) आयन
9. टेट्राकार्बोनिलनिकिल (0)।

प्रश्न 9.8
उपसहसंयोजन यौगिकों के लिए सम्भावित विभिन्न प्रकार की समावयवताओं को सूचीबद्ध कीजिए तथा प्रत्येक का एक उदाहरण दीजिए।
उत्तर:
उपसहसंयोजन यौगिकों में दो प्रमुख प्रकार की समावयवताएँ ज्ञात हैं। इनमें से प्रत्येक को पुनः प्रविभाजित किया जा सकता है।

1. त्रिविम समावयवता:
(क) ज्यामितीय समावयवता; जैसे –

2. संरचनात्मक समावयवता:
(क) बन्धनी समावयवता; जैसे –
[Co(NH₃)₅(NO₂)] Cl₂
तथा [Co(NH₃)₅(ONO)] Cl₂

(ख) उपसहसंयोजन समावयवता; जैसे –
[Co(NH₃)₆] [Cr(CN)₆]
तथा [Cr(NH₃)₆] [Co(CN)₆]

(ग) आयनन समावयवता; जैसे –
[Co(NH₃)₄ Cl₂] NO₂
तथा [Co(NH₃)₄ (NO₂Cl)] Cl

(घ) विलायकयोजन समावयवता; जैसे –
[Cr(H₂O)₆] Cl₃
तथा [Cr(H₂O)₅ Cl] Cl₂.H₂O

प्रश्न 9.9
निम्नलिखित उपसहसंयोजन सत्ता में कितने ज्यामितीय समावयव सम्भव हैं?
(क) [Cr(C₂O₄)₃]
(ख) [Co(NH₃)₃ Cl₃]
उत्तर:
(क) कोई ज्यामितीय समावयव सम्भव नहीं है।
(ख) दो ज्यामितीय समावयव फलकीय तथा रेखांशिक समावयव सम्भव हैं।

प्रश्न 9.10
निम्नलिखित के प्रकाशिक समावयवों की संरचनाएँ बनाइए –

1. [Cr(C₂O₄)₃]^3-
2. [PtCl₂(en)₂]²⁺
3. [Cr(NH₃)₂Cl₂(en)]⁺

उत्तर:
1. [Cr(C₂O₄)₃]^3-

2. [PtCl₂(en)₂]²⁺

3. [Cr(NH₃)₂Cl₂(en)]⁺

प्रश्न 9.11
निम्नलिखित के सभी समावयवों (ज्यामितीय व ध्रुवण) की संरचनाएँ बनाइए –

1. [CoCl₂(en)₂]⁺
2. [Co(NH₃)Cl(en)₂]²⁺
3. [Co(NH₃)₂Cl₂(en)]⁺

उत्तर:
1. [CoCl₂(en)₂]⁺

2. [Co(NH₃)Cl(en)₂]²⁺

3. [Co(NH₃)₂Cl₂(en)₂]²⁺

प्रश्न 9.12
[Pt (NH₃) (Br)(CI) (Py)] के सभी ज्यामितीय समावयव लिखिए। इनमें से कितने ध्रुवण समावयवता दर्शाएँगे?
उत्तर:
इसके तीन ज्यामितीय समावयव सम्भव हैं।

ये समायव ध्रुवण समावयवता नहीं दर्शाते हैं। ध्रुवण समावयवता वर्ग समतली अथवा चतुष्फलकीय संकुलों में पाई जाती है जबकि इनमें असममिताकार कीलेटिंग लीगेंड हैं।

प्रश्न 9.13
जलीय कॉपर सल्फेट विलयन (नीले रंग का), निम्नलिखित प्रेक्षण दर्शाता है –

1. जलीय पोटैशियम फ्लुओराइड के साथ हरा रंग
2. जलीय पोटैशियम क्लोराइड के साथ चमकीला हरा रंग। उपर्युक्त प्रायोगिक परिणामों को समझाइए।

उत्तर:
जलीय CusO₄ विलयन [Cu(H₂O)₄]²⁺ SO₄^2-, H₂O के रूप में पाया जाता है जिसका नीला रंग [Cu(H₂O)₄]²⁺ आयनों के कारण होता है।

1. जब पोटैशियम फ्लुओराइड मिलाया जाता है, तब दुर्बल H₂O लिगेण्ड F^– लिगेण्डों द्वारा प्रतिस्थापित होकर [CuF₄]^2- आयन बनाते हैं जो एक हरा अवक्षेप होता है।

2. जब पोटैशियम क्लोराइड (KCl) मिलाया जाता है, तब Cl^– लिगेण्ड दुर्बल H₂O लिगेण्डों को प्रतिस्थापित करके [CuCl₄]^2- आयन बनाते हैं जिसका चमकीला हरा रंग होता है।

प्रश्न 9.14
कॉपर सल्फेट के जलीय विलयन में जलीय KCN को आधिक्य में मिलाने पर बनने वाली उपसहसंयोजन सत्ता क्या होगी? इस विलयन में जब H₂S गैस प्रवाहित की जाती है तो कॉपर सल्फाइड का अवक्षेप क्यों नहीं प्राप्त होता?
उत्तर:
कॉपर सल्फेट के जलीय विलयन में जलीय KCN विलयन मिलाने पर पोटैशियम टेट्रासाइनो क्यूप्रेट (II) का संकुल बनता है।
2 CuSO₄(aq) + 10KCN (aq) → 2K₃ [Cu(CN)₄](aq) + 2K₂SO₄(aq)
चूँकि CN^– एक प्रबल लिगेण्ड है, अत: संकुल स्थाई होता है। H₂S गैस को प्रवाहित करने पर यह विखण्डित नहीं होता है तथा CuS का कोई अवक्षेप नहीं बनता।

प्रश्न 9.15
संयोजकता आबन्ध सिद्धान्त के आधार पर निम्नलिखित उपसहसंयोजन सत्ता में आबन्ध की प्रकृति की विवेचना कीजिए –
(क) [Fe(CN)₆^4-
(ख) [FeF₆]^3-
(ग) Co(C₂O₄)₃]^3-
(घ) [CoF₆]^3-
उत्तर:
(क) [Fe(CN)₆]^4- इस संकुल आयन में आयरन की ऑक्सीकरण अवस्था +2 है।
Fe का इलेक्ट्रॉनिक विन्यास = [Ar] 3d⁶ 4s²
Fe²⁺ का इलेक्ट्रॉनिक विन्यास = [Ar] 3d⁶
छह सायनाइड आयनों से छह इलेक्ट्रॉन युग्मों को स्थान देने के लिए आयरन (II) आयन को छह रिक्त कक्षक उपलब्ध करने चाहिए। ऐसा निम्नलिखित संकरण पद्धति के द्वारा प्राप्त किया जा सकता है जिसमें d – उपकोश के इलेक्ट्रॉन युगलित हो जाते हैं, चूँकि CN आयन प्रबल क्षेत्र लिगेण्ड हैं।

अतः छह सायनाइड आयनों से छड़ इलेक्ट्रॉन युग्म आयरन (II) आयन के छह संकरित कक्षकों को अध्यासित कर लेते हैं। इस प्रकार किसी भी कक्षक में अयुगलित इलेक्ट्रॉन नहीं होते हैं, इसलिए [Fe(CN)₆]^4- प्रतिचुम्बकत्व दर्शाता है। अतः [Fe(CN)₆]^4- प्रतिचुम्बकीय तथा अष्टफलकीय है।

(ख) [FeF₆]^3-:
यह संकुल उच्च चक्रण (या चक्रण मुक्त) या बाह्य संकुल है, चूँकि केन्द्रीय धातु आयन, Fe (III) संकरण के लिए nd-कक्षकों का प्रयोग करता है। यह एक ङ्केअष्टफलकीय संकुला है जिसमें sp³ d² संकरण होता है। प्रत्येक कक्षक में छह फ्लुओराइड आयनों से एक-एक एकाकी इलेक्ट्रॉन-युग्म स्थान प्राप्त करता है जैसा कि निम्नांकित चित्र में दर्शाया गया है।

चूँकि संकुल में पाँच अयुगलित इलेक्ट्रॉन हैं, यह अनुचुम्बकीय है।

(ग) [Co(C₂O₄)^3-:
Co(Z = 27) का इलेक्ट्रॉनिक विन्यास: [Ar] 4s² 3d⁷
Co³⁺ का इलेक्ट्रॉनिक विन्यास: [Ar] 4s⁰ 4d⁶
C₂O₄^2- प्रबल क्षेत्रीय लिगेण्ड है, जिसके कारण इलेक्ट्रॉनों का युग्मन होता है।

अतः स्पष्ट है कि [Co(C₂O₄)₃]^3- प्रतिचुम्बकीय, अष्टफलकीय संकुल है।

(घ) [CoF₆]^3- – Co(27): [Ar] 4s² 3d⁷ Co³⁺: [Ar] 4s⁰ 3d⁶

F^– एक दुर्बल लिगेण्ड होने के कारण इलेक्ट्रॉनों का युग्मन नहीं कर सकता है।

अतः [CoF₆]^3- अनुचुम्बकीय तथा अष्टफलकीय संकुल है।

प्रश्न 9.16
अष्टफलकीय क्रिस्टल क्षेत्र में d-कक्षकों के विपाटन को दर्शाने के लिए चित्र बनाइए।
उत्तर:
माना छह लिगण्ड कार्तिक अक्षों के अनुदिश सममित रूप में स्थित हैं तथा धातु परमाणु मूल बिन्दु पर है। लिगेण्ड के निकट पर d – कक्षकों की ऊर्जा में मुक्त आयनों की तुलना में अपेक्षित वृद्धि होती है जैसा कि गोलीय क्रिस्टल क्षेत्र की स्थिति में होता है।

अक्षों के अनुदिश कक्षक (dz² तथा \(d_{x}^{2}-y^{2}\)) d_xy, d_yz तथा d_zx कक्षकों की तुलना में अधिक प्रबलता से प्रतिकर्षित होते हैं तथा इनमें अक्षों के मध्य निर्देशित पालियाँ (lobes) होती गोलीय क्रिस्टल क्षेत्र में औसत ऊर्जा की अपेक्षा dz² तथा \(d_{x}^{2}-y^{2}\) कक्षक ऊर्जा में बढ़ जाते हैं तब d_xy, d_yz, d_xz कक्षक ऊर्जा में न्यून हो जाते हैं।

चित्र – अष्टफलीय क्रिस्टल क्षेत्र में d – कक्षकों का विघटन
अतः d – कक्षकों का समभ्रंश समूह (degenerate set) दो समूहों में विघटित हो जाता है – निम्न ऊर्जा कक्षक समूह t_2g तथा उच्च ऊर्जा कक्षक समूह e_g ऊर्जा ∆0 द्वारा पृथक्कृत होती

प्रश्न 9.17
स्पेक्ट्रमीरासायनिक श्रेणी क्या है? दुर्बल क्षेत्र लिगेण्ड तथा प्रबल क्षेत्र लिगेण्ड में अन्तर स्पष्ट कीजिए।
उत्तरः
स्पेक्ट्रमीरासायनिक श्रेणी:
क्रिस्टल क्षेत्र विपाटन, ∆₀ लिगेण्ड तथा धातु आयन पर विद्यमान आवेश से उत्पन्न क्षेत्र पर निर्भर करता है। कुछ लिगेण्ड प्रबल क्षेत्र उत्पन्न कर सकते हैं तथा ऐसी स्थिति में विपाटन अधिक होता है, जबकि अन्य दुर्बल क्षेत्र उत्पन्न करते हैं जिसके फलस्वरूप d – कक्षकों का विपाटन कम होता है। सामान्यत: लिगेण्डों को उनके बढ़ती हुई क्षेत्र प्रबलता के क्रम में एक श्रेणी में निम्नानुसार व्यवस्थित किया जा सकता है –
I^–Br^– < SCN^– < Cl^– < S^2- < F^– < OH^– C₂
O₄^2- < H₂O < NCS^– <edta^4- < NH₃ < en < CN^– < Co इस प्रकार की श्रेणी स्पेक्ट्रमीरासायनिक श्रेणी (spectrochemical series) कहलाती है।

यह विभिन्न लिगेण्डों के साथ बने संकुलों द्वारा प्रकाश के अवशोषण पर आधारित प्रायोगिक तथ्यों द्वारा निर्धारित श्रेणी हैं। प्रबल क्षेत्र लिगेण्ड के मध्य अन्तर ऐसे लिगेण्ड को जिनकी क्रिस्टल क्षेत्र विपाटन ऊर्जा (CFSE), ∆₀ का मान कम होता है, दुर्बल क्षेत्र लिगेण्ड कहते हैं।

दुर्बल क्षेत्र लिगेण्ड के कारण इलेक्ट्रॉनों का युग्मन नहीं होता तथा. ये उच्च चक्रण संकुल बनाते हैं। ऐसे लिगेण्ड को जिनकी क्रिस्टल क्षेत्र विपाटन ऊर्जा, ∆₀ का मान अधिक होता है, प्रबल क्षेत्र लिगेण्ड कहते हैं। प्रबल क्षेत्र लिगेण्ड के कारण इलेक्ट्रॉनों का युग्मन होता है तथा ये निम्न चक्रण संकुल बनाते हैं।

प्रश्न 9.18
क्रिस्टल क्षेत्र विपाटन ऊर्जा क्या है? उपसहसंयोजन सत्ता में d – कक्षकों का वास्तविक विन्यास ∆₀ के मान के आधार पर कैसे निर्धारित किया जाता है?
उत्तर:
जब लिगेण्ड संक्रमण धातु आयन के निकट जाता है, तब d – कक्षक दो समुच्चयों में विपाटित हो जाते हैं, एक निम्न ऊर्जा के साथ तथा दूसरा उच्च ऊर्जा के साथा कक्षकों के इन दो समुच्चयों के बीच ऊर्जा का अन्तर अष्टफलकीय क्षेत्र के लिए क्रिस्टल क्षेत्र विपाटन ऊर्जा ∆₀ कहलाता है।

यदि ∆₀ < P (युग्मन ऊर्जा) तो चौथा इलेक्ट्रॉन किसी एक e_g कक्षक में प्रवेश करता है तथा \(t_{2 g}^{3} e_{g}^{1}\) विन्यास देकर उच्च चक्रण संकुल बनाता है। ऐसे लिगेण्ड (जिनके लिए, ∆₀ < P) दुर्बल क्षेत्र लिगेण्ड कहलाते हैं।
यदि ∆₀ < P, तो चौथा इलेक्ट्रॉन किसी एक t_2g कक्षक में युग्मित होता है तथा \(t_{2 g}^{4} e_{g}^{0}\) विन्यास देकर अल्प चक्रण संकुल बनाता है। ऐसे लिगेण्ड (जिनके लिए, ∆₀ > P) प्रबल क्षेत्र लिगेण्ड कहलाते हैं।

प्रश्न 9.19
[Cr(NH₃)₆]³⁺ अनुचुम्बकीय है, जबकि [Ni(CN)₄]^2- प्रतिचुम्बकीय, समझाइए क्यों?
उत्तरः
[Cr(NH₃)₆]³⁺ का निर्माण:
[Cr(NH₃)₆]³⁺ आयन में क्रोमियम की ऑक्सीकरण अवस्था +3 है, जिसका इलेक्ट्रॉनिक विन्यास [Ar] 3d⁵ 4s¹ है। संकरण को निम्न प्रकार से दिखाया गया है –

Cr³⁺ आयन अमोनिया के छह अणुओं से छह इलेक्ट्रॉन युग्मों के लिए यह रिक्त कक्षक उपलब्ध हैं। इसके फलस्वरूप संकुल [Cr(NH₃₆)³⁺ में d²sp³ संकरण अष्टफलकीय होता है।

संकुल में इन अयुगलित इलेक्ट्रॉनों की उपस्थिति के कारण यह वर्ग समतल संकुलों के संकरण d sp² है जिसे निम्नवत् दर्शाया जा सकता है। प्रत्येक संकरित कक्षक सायनाइड आयन से एक इलेक्ट्रॉन युग्म ग्रहण करता है, जिससे अयुगलित इलेक्ट्रॉनों की अनुपस्थिति [Ni(CN)₄]^2- के प्रतिचुम्बकीय व्यवहार की पुष्टि होती है।

प्रश्न 9.20
[Ni(H₂O)₆]²⁺ का विलयन हरा है, परन्तु [Ni(CN)₄]^2- का विलयन रंगहीन है। समझाइए।
उत्तर:
चूँकि H₂O दुर्बल लिगण्डों को निरूपित करता है, अतः ये कोई इलेक्ट्रान नहीं बनाते हैं। [Ni(H₂O)₆]²⁺ में Ni, 3d⁸ विन्यास के साथ +2 ऑक्सीकरण अवस्था में है अर्थात् संकुल में दो अयुगलित इलेक्ट्रॉन हैं, अत: यह रंगीन होता है। d-d संक्रमण लाल प्रकाश अवशोषित करके पूरक हरा रंग उत्सर्जित करता है।

[Ni(CN)₄]^2- में भी Ni, 3d⁸ विन्यास के साथ +2 ऑक्सीकरण अवस्था में है, परन्तु प्रबल CN^– लिगेण्ड की उपस्थिति में 3d – कक्षक में दो अयुगलित इलेक्ट्रॉन गलित हो जाते हैं। अतः कोई अयुगलित इलेक्ट्रॉन नहीं होता; अत: यह रंगहीन होता है।

प्रश्न 9.21
[Fe(CN)₆]^4- तथा [Fe(H₂O)₆]²⁺ के तनु विलयनों के रंग भिन्न होते हैं। क्यों?
उत्तर:
दोनों संकलों में, Fe की ऑक्सीकरण अवस्था +2 है अर्थात् इसमें चार अयुगलित इलेक्ट्रॉन हैं। दुर्बल H₂O लिगण्ड की उपस्थिति में ये युगलित नहीं हो पाते हैं जबकि CN^– प्रबल लिगण्ड की उपस्थिति में ये युग्मित होकर कोई अयुगलित इलेक्ट्रॉन नहीं छोड़ते हैं। अत: अयुगलित इलेक्ट्रॉनों की उपस्थिति में अन्तर के कारण इनके तनु विलयनों में भिन्न रंग होते हैं।

प्रश्न 9.22
धातु कार्बोनिलों में आबन्ध की प्रकृति की विवेचना कीजिए।
उत्तर:
धातु कार्बोनिलों में आबन्ध की प्रकृति:
धातु कार्बोनिलों के धातु कार्बन आबन्ध में s तथा p के गुण पाये जाते हैं। M – C सिग्मा (σ) आबन्ध कार्बोनिल समूह के कार्बन में उपस्थित इलेक्ट्रॉन युगल को धातु के रिक्त कक्षक में दान करने से बनता है।

π – अतिव्यापन जिसमें पूरित धातु d – कक्षकों से इलेक्ट्रॉनों का CO के रिक्त प्रतिआबन्धन π* आण्विक कक्षकों में दान निहित होता है, इसके परिणामस्वरूप M → Cπ आबन्ध बनता है। धातु से लिगेण्ड का आबन्ध एक सहक्रियाशीलता का प्रभाव उत्पन्न करता है जो CO व धातु के मध्य आबन्ध को मजबूत बनाता है।

धातु कार्बोनिलों में आबन्धन निम्न प्रकार से प्रदर्शित है –

चित्र-कार्बोनिल संकुल में सहक्रियाशीलता आबन्धन अन्योयक्रिया का उदाहरण

प्रश्न 9.23
निम्नलिखित संकुलों में केन्द्रीय धातु आयन की ऑक्सीकरण अवस्था, d – कक्षकों का अधिग्रहण एवं उपसहसंयोजन संख्या बतलाइए –

1. K₃[C₂O₄₃]
2. समपक्ष – [Cr(en)₂Cl₂]Cl
3. (NH₄)₂[CoF₄] ङ्के
4. [Mn(H₂O)₆]SO₄

उत्तर:
1. संकुल:
K₃[Co(C₂O₄)₃]
ऑक्सीकरण अवस्था –
1 + x + 3(-2) = 0
x = +3
उपसहसंयोजन संख्या: 6 (∵\(\mathrm{C}_{2} \mathrm{O}_{4}^{2-}\) द्विदुन्तर है)
d – कक्षक अध्यासन : 3d⁶ = \(t_{2 g}^{6} e_{g}^{0}\)

2. संकुल समपक्ष:
[Cr(en)₂Cl₂]Cl
ऑक्सीकरण अवस्था:
या x + 0 + 2(-1) = +1 या
x = +3

उपसहसंयोजन संख्या: 6

d – कक्षक अध्यासन:
3d³ = \(t_{2 g}^{3}\)

3. संकुल (NH₄)₂ [CoF₄]:
थैऑक्सीकरण अवस्था:
x + 4(-1) = -2
x = +2
उपसहसंयोजन संख्या: 4

d – कक्षक अध्ययासन:
3d⁷ = \(e_{g}^{4} t_{2 g}^{3}\)

4. संकुल [Mn(H₂O)₆] SO₄
ऑक्सीकरण अवस्था:
x + 0 = +2
x = +2

उपसहसंयोजन संख्या: 6

d – कक्षक अध्यासन:
3d⁵ = \(t_{2 g}^{3} e_{g}^{2}\)

प्रश्न 9.24
निम्नलिखित संकलों के IUPAC नाम लिखिए तथा ऑक्सीकरण अवस्था, इलेक्ट्रॉनिक विन्यास और उपसहसंयोजन संख्या दर्शाइए। संकुल का त्रिविम रसायन तथा चुम्बकीय आघूर्ण भी बतलाइए –

1. K[Cr(H₂O)₂ (C₂O₄)₂].3H₂O
2. [CrCl₃(Py)₃]
3. [Co(NH₃)₅Cl]Cl₂
4. Cs[FeCl₄]
5. K₄[Mn(CN)₆]

उत्तर:
1. K[Cr(H₂O)₂ (C₂O₄)₂].3H₂O का IUPAC
नाम-पोटैशियम डाइऐक्वाऑक्सेलेटो क्रोमेट (III) हाइड्रेट
K[Cr(H₂O)(C₂O₄)₂].3H₂O में Cr की ऑक्सीकरण अवस्था,
+ 1 + x + 0 – 4 = 0
x = +3
क्रोमियम की उपसहसंयोजन संख्या 6 है।
Cr(24) : 4s¹ 3d⁵
Cr³⁺ : 4s⁰ 3d³

2. [CrCl₃(Py)₃] का IUPAC
नाम-ट्राइक्लोरिडोट्राइपिरिडीन क्रोमियम (III)
क्रोमियम की उपसहसंयोजन संख्या 6 है।
[CrCl₃ (Py)₃] में Cr की ऑक्सीकरण अवस्था +3 है।

चुम्बकीय आघूर्ण (µ) = \(\sqrt{3×5}\) = \(\sqrt{15}\) = 3.87 BM

3. [Co(NH₃)₅ Cl]Cl₂ का IUPAC
पेन्टाऐम्मीनक्लोरिडोकोबाल्ट (III) क्लोराइड
Co की ऑक्सीकरण संख्या +3 है।
Co की उपसहसंयोजन संख्या 6 है।
Cr (27) : 4s² 3d⁷
Cr³⁺ : 4s⁰3d⁶

चुम्बकीय आघूर्ण (µ) = 0

4. Cs[FeCl₄] का IUPAC नाम –
सीजियम टेट्राक्लोरोफेरेट (III)
Fe की ऑक्सीकरण अवस्था +3 है।
Fe की उपसहसंयोजन संख्या 4 है।
Fe (26) : 4s² 3d⁶
Fe³⁺ : 4s⁰ 3d⁵

यह 5 – अयुगलित इलेक्ट्रॉनों की उपस्थिति के कारण अनुचुम्बकीय है।
चुम्बकीय आघूर्ण
(µ) = \(\sqrt{n(n+2)}\) = \(\sqrt{5×7}\) = \(\sqrt{35}\) = 5.92 BM

5. K₄[Mn(CN)₆] का IUPAC नाम –
पोटैशियम हेक्सासायनोमैंगनीज (II) Mn की ऑक्सीकरण संख्या +2 है।
Mn की उपसहसंयोजन संख्या 6 है।
Mn(25) : 4s² 3d⁵
Mn²⁺ : 4s⁰ 3d⁵

चुम्बकीय आघूर्ण
(µ) = \(\sqrt{n(n+2)}\) = \(\sqrt{1(1+2)}\) = \(\sqrt{3)}\) = 1.732 BM.

प्रश्न 9.25
उपसहसंयोजन यौगिक के विलयन में स्थायित्व से आप क्या समझते हैं? संकुलों का स्थायित्व को प्रभावित करने वाले कारकों का उल्लेख कीजिए।
उत्तर:
विलयन में उपसहसंयोजन यौगिकों का स्थायित्व (Stability of Coordination of Compounds in Solution):
अधिकांश संकुल अत्यधिक स्थायी होते हैं। धातु आयन तथा लिगेण्ड के बीच अन्योन्यक्रिया को लूइस अम्ल-क्षार अभिक्रिया के समान माना जाता है।

यदि अन्योन्यक्रिया प्रबल होगी तो बनने वाला संकुल ऊष्मागतिकीय रूप से अत्यधिक स्थायी होगा। विलयन में संकुल के स्थायित्व का अर्थ है-साम्य् अवस्था पर भाग ले रही दो स्पीशीज के मध्य संगुणन की मात्रा का मान। संगुणन के लिए साम्य स्थिरांक (स्थायित्व या विरचन) का परिमाण गुणात्मक रूप को स्थायित्व को प्रकट करता है। इस प्रकार यदि हम निम्नांकित प्रकार की अभिक्रिया को लें –
M + 4L ⇄ ML₄
K = \(\frac{\left[\mathrm{ML}_{4}\right]}{[\mathrm{M}][\mathrm{L}]^{4}}\)
साम्य स्थिरांक का मान जितना अधिक होगा, ML₄ की विलयन में मात्रा उतनी ही अधिक होगी। विलयन में मुक्त धातु आयनों का अस्तित्व नगण्य होता है। अतः M सामान्यतः विलायक अणुओं से घिरा होगा जो लिगेण्ड अणुओं, L, से प्रतिस्पर्धा करेंगे तथा धीरे – धीरे उनसे प्रतिस्तापित हो जाएंगे।

संकलों के स्थायित्व को प्रभावित करने वाले कारक (Factors affecting the Stability of a Complex):
संकुलों का स्थायित्व निम्नलिखित कारकों पर निर्भर करता है –

(1) केन्द्रीय आयन की प्रकृति (Nature of Central Ion):

(i) केन्द्रीय धातु आयन पर आवेश (Charge on central metal ion):
सामान्यतया केन्द्रीय आयन पर आवेश घनत्व जितना अधिकर होता है, इसके संकुलों का स्थायित्व भी उतना ही अधिक होता है। दूसरे शब्दों में किसी आयन पर आवेश अधिक तथा आकार छोटा होने पर अर्थात् आयन का आवेश/त्रिज्या अनुपात अधिक होने पर इसके संकुलों का स्थायित्व अधिक होता है। उदाहरणार्थ – Fe²⁺ आयन की तुलना में Fe³⁺ आयन उच्च आवेश वहन करते हैं, परन्तु इनके आकार समान होते हैं।

इसलिए Fe²⁺ आयन की तुलना में Fe³⁺ पर आवेश घनत्व उच्च होता है, इसलिए Fe³⁺ आयन के संकुल अधिक स्थायी होते हैं।
Fe³⁺ + 6CN^– → [Fe(CN)₆]^3-; K = 1.2 × 10³¹
Fe²⁺ + 6CN^– → [Fe(CN)₆]^4-; K = 1.8 × 10⁶

(ii) धातु आयन का आकार (Size of metal ion):
धातु आयन का आकार घटने पर संकुल का स्थायित्व बढ़ता है। यदि हम द्विसंयोजी धातु आयन पर विचार करें तो इनके संकुलों का स्थायित्व केन्द्रीय धातु आयन की आयनिक त्रिज्या बढ़ने के साथ बढ़ता है।

इसलिए स्थायित्व का क्रम इस प्रकार है –
Mn²¹ < Fe²⁺ < Co²⁺ < Ni²⁺ < Cu²⁺ < Zn²⁺ यह क्रम इरविंग विलियम का स्थायित्व क्रम कहलाता है।

(iii) धातु आयन की विद्युतऋणात्मकता या आवेश वितरण (Electronegativity or Charge distribution of metal ion):
संकुल आयन का स्थायित्व धातु आयन पर इलेक्ट्रॉन आवेश वितरण से भी सम्बन्धित होता है। आरलेण्ड, चैट तथा डेविस के अनुसार धातु आयनों को दो प्रकारों में वर्गीकृत किया जा सकता है –

(क) वर्ग ‘a’ ग्राही (Class ‘a’ acceptors):
ये पूर्णतया विद्युतधनात्मक धातुएँ होती हैं तथा इनमें वर्ग 1 तथा 2 की धातुएँ सम्मिलित होती हैं। इनके अतिरिक्त आन्तरसंक्रमण धातुएँ तथा संक्रमण श्रेणी के पूर्व सदस्य (वर्ग 3 से 6 तक), जिनमें अक्रिय गैस विन्यास से कुछ इलेक्ट्रॉन अधिक होते हैं, भी इस वर्ग में सम्मिलित होते हैं। ये N, O तथा F दाता परमाणुओं से युक्त लिगण्डों के साथ अत्यधिक स्थायी उपसहसंयोजक सत्ता बनाते है।

(ख) वर्ग ‘b’ ग्राही (Class ‘b’ acceptors):
ये बहुत कम विद्युतधनात्मक होते हैं। इनमें भारी धातुएँ; जैसे – Rh, Pd, Ag, Ir, Pt, Au, Hg, Pb आदि, जिनमें भरित d – कक्षक होते हैं, सम्मिलित होती हैं। ये उन लिगण्डों के साथ स्थायी संकुल बनाती हैं जिनमें N, O तथा F वर्ग के भारी सदस्य दाता परमाणु होते हैं।

(iv) कीलेट प्रभाव (Chelate effect):
स्थायित्व कीलेट वलयों के निर्माण पर भी निर्भर करता है। यदि L एक एकदन्तुर लिगेण्ड तथा L – L द्विदन्तुर लिगेण्ड हो तथा यदि L तथा L – L के दाता परमाणु एक ही तत्त्व के हों, तब L – L, L को प्रतिस्थापित कर देगा। कीलेशन के कारण यह स्थायित्व कीलेट प्रभाव कहलाता है। 5 तथा 6 सदस्यीय वलयों में कीलेट प्रभाव अधिकतम होता है। सामान्य रूप में वलय संकुल को अधिक स्थायित्व प्रदान करती है।

(v) वृहदचक्रीय प्रभाव (Macrocyclic effect):
यदि एक बहुदन्तुर लिगेण्ड चक्रीय है तथा कोई अनपयुक्त त्रिविम प्रभाव नहीं है तो बनने वाला संकुल बिना चक्रीय लिगेण्ड के सम्बन्धित संकुल की तुलना में अधिक स्थायी होगा। यह वृहदचक्रीय प्रभाव कहलाता है।

(2) लिगेण्ड की प्रकृति (Nature of Ligand):

(i) क्षारीय सामर्थ्य (Basic strength):
लिगेण्ड जितना अधिक क्षारीय होगा, उतनी ही अधिक सरलता से अपने एकाकी इलेक्ट्रॉन-युग्म को दान देने में होगी, इसलिए इससे बनने वाले संकुल उतने ही अधिक स्थायी होंगे। अत: CN^– तथा F^– आयन एवं NH₃, जो प्रबल क्षार हैं, अच्छे लिगेण्ड भी हैं तथा अनेक स्थायी संकुल बनाते हैं।

(ii) लिगण्डों का आकार तथा आवेश (Size and charge of ligands):
ऋणायनी लिगण्डों के लिए आवेश उच्च तथा आकार छोटा होने पर बनने वाला संकुल अधिक स्थायी होता है। अत: F^– अधिक स्थायी संकतुल देता है, परन्तु Cl^– आयन नहीं।

प्रश्न 9.26
कीलेट प्रभाव से क्या तात्पर्य है? एक उदाहरण दीजिए।
उत्तर:
जब एक द्विदन्तुर या बहुदन्तुर लिगेण्ड में दाता परमाणु इस प्रकार स्थित होते हैं कि जब वे केन्द्रीय धातु आयन से उपसहसंयोजित होते हैं, तब एक पाँच या छ: सदस्यीय वलय बनती है तो इस प्रभाव को कीलेट प्रभाव कहते हैं।
उदाहरण:

प्रश्न 9.27
प्रत्येक का एक उदाहरण देते हुए निम्नलिखित में उपसहसंयोजन यौगिकों की भूमिका की संक्षिप्त विवेचना कीजिए:

1. जैव-प्रणालियाँ
2. विश्लेषणात्मक रसायन
3. औषध रसायन
4. धातुओं का निष्कर्षण/धातुकर्म।

उत्तर:
1. जैव प्रणालियाँ:
उपसहसंयोजन यौगिक जैव-तन्त्र में बहुत ही महत्वपूर्ण हैं। प्रकाश-संश्लेषण के लिए उत्तरदायी वर्णक, क्लोरोफिल मैग्नीशियम का उपसहसंयोजन यौगिक हैं। रक्त का लाल वर्णक हीमोग्लोबिन, जो कि ऑक्सीजन का वाहक है, आयरन का एक उपसहसंयोजन यौगिक है।

विटामिन B₁₂ सायनोकोबालऐमीन, प्रतिप्राणाली अरक्तता कारक (antipernicious anaemia factor), कोबाल्ट का एक उपसहसंयोजन यौगिक है। जैविक महत्त्व के अन्य धातु आयन युक्त उपसहसंयोजन यौगिक; जैसे- कार्बोक्सीपेप्टिडेज – A (carboxypeptidase A) तथा कार्बोनिक एनहाइड्रेज (carbonic anhydrase) (जैव-प्रणाली के उत्प्रेरक) एन्जाइम हैं।

2. विश्लेषणात्मक रसायन:
गुणात्मक (qualitative) तथा मात्रात्मक (quantitative) रासायनिक विश्लेषणों में उपसहसंयोजन यौगिकों के अनेक उपयोग हैं। अनेक परिचित रंगीन अभिक्रियाएँ जिनमें धातु आयनों के साथ अनेक लिगण्डों (विशेष रूप से कीलेट लिगण्ड) की उपसहसंयोजन सत्ता बनने के कारण रंग उत्पन्न होता है, चिरसम्मत (classical) तथा यान्त्रिक (instrumental) विधियों द्वारा धातु आयनों की पहचान व उनके मात्रात्मक आकलन का आधार हैं। ऐसे अभिकर्मकों के उदाहरण हैं – EDTA, DMG (डाइमेथिल ग्लाइऑक्सिम), α – नाइट्रोसो – β – नैफ्थॉल आदि।

3. औषध रसायन:
औषध रसायन में कीलेट चिकित्सा के उपयोग में अभिरुचि बढ़ रही है। इसका एक उदाहरण है-पौधे/जीव-जन्तु निकायों में विषैले अनुपात में विद्यमान धातुओं के द्वारा उत्पन्न समस्याओं का उपचार।

इस प्रकार कॉपर तथा आयरन की अधिकता को D – पेनिसिलऐमीन तथा डेसफरीऑक्सिम B लिगण्डों के साथ उपसहसंयोजन यौगिक बनाकर दूर किया जाता है। EDTA को लेड की विषाक्तता के उपचार में प्रयुक्त किया जाता है। प्लैटिनम के कुछ उपसहसंयोजन यौगिक ट्यूमर वृद्धि को प्रभावी रूप से रोकते हैं। उदाहरण हैं-समपक्ष-प्लैटिन (cis-platin) तथा सम्बन्धित यौगिका।

4. धातुओं का निष्कर्षण/धातुकर्म:
धातुओं की कुछ प्रमुख निष्कर्षण विधियों में; जैसे-सिल्वर तथा गोल्ड के लिए संकुल विचन का उपयोग होता है। उदाहरणार्थ: ऑक्सीजन तथा जल की उपस्थिति में गोल्ड सायनाइड आयन से संयोजित होकर जलीय विलयन में उपसहसंयोजन सत्ता, [Au(CN)₂]^– बनाता है। इस विलयन में जिंक मिलाकर गोल्ड को पृथक् किया जा सकता हैं।

प्रश्न 9.28
संकुल [Co(NH₃)₆] Cl₂ से विलयन में कितने आयन उत्पन्न होंगे –

1. 6
2. 4
3. 3
4. 2

उत्तर:
संकुल [Co(NH₃)₆] Cl₂ विलयन में तीन आयनों में वियोजित होता है –

अतः सही विकल्प (iii) है।

प्रश्न 9.29
निम्नलिखित आयनों में से किसके चुम्बकीय आघूर्ण का मान सर्वाधिक होगा?

1. [Cr(H₂O)₆]³⁺
2. [Fe(H₂O)₆]²⁺
3. [Zn(H₂O₆]²⁺

उत्तर:

1. Cr³⁺ का इलेक्ट्रॉनिक विन्यास = 3d³; अयुगमित इलेक्ट्रॉन = 3
2. Fe²⁺ का इलेक्ट्रॉनिक विन्यास = 3d⁶; अयुगमित इलेक्ट्रॉन = 4
3. Zn²⁺ का इलेक्ट्रॉनिक विन्यास = 3d¹⁰; अयुगमित इलेक्ट्रॉन = 0

चूँकि n = 4 सबसे अधिक है, अत: इसके लिए चुम्बकीय आघूर्ण सर्वाधिक होगा। अतः सही विकल्प (ii) है।

प्रश्न 9.30
K[Co(CO)₄] में कोबाल्ट की ऑक्सीकरण संख्या है:

1. +1
2. +3
3. -1
4. -3

उत्तर:
माना K [Co(CO)₄]^-1 में Co की आ० सं० x है।
x + 0 = -1 या x = -1
अतः सही विकल्प (iii) है।

प्रश्न 9.31
निम्नलिखित में सर्वाधिक स्थायी संकुल है:

1. [Fe(H₂O)₆]²⁺
2. [Fe(NH₃)₆]³⁺
3. [Fe(C₂O₄)₃]^3-
4. [FeCl₆]^3-

उत्तर:
दिये गए संकुलों में Fe की आ० सं० +3 है। चूंकि तीन \(\mathrm{C}_{2} \mathrm{O}_{4}^{2-}\) आयन कीलेटलिगेण्ड हैं, अत: यह संकुल एक कीलेट है। अतः सही विकल्प (iii) है।

प्रश्न 9.32
निम्नलिखित के लिए दृश्य प्रकाश में अवशोषण की तरंगदैर्ध्य का सही क्रम क्या होगा?
[Ni(NO₂)₆]^2-, [Ni(NH₃)₆]²⁺, [Ni(H₂O)²⁺
उत्तर:
चूँकि इन सभी संकुलों में धातु आयन (Ni²⁺) है अत: स्पेक्ट्रमी रासायनिक श्रेणी के अनुसार उपस्थित लिगण्डों के बढ़ते क्षेत्र सामर्थ्य निम्न प्रकार है:
H₂O < NH₃ < NO^–₂
अत: उत्तेजन हेतु अवशोषित ऊर्जाओं का क्रम निम्नवत् है:
[Ni(H₂O)₆]²⁺ < [Ni(NH₃)₆]²⁺ < [Ni(NO₂)₆]^4-
चूँकि E = \(\frac{hc}{λ}\) अर्थात् E ∝ \(\frac{1}{λ}\) अत: अवशोषित तरंदैर्ध्य विपरीत क्रम में होगी।