CBSE Class 12

CBSE Sample Papers for Class 12 English Core Paper 1 are part of CBSE Sample Papers for Class 12 English Core. Here we have given CBSE Sample Papers for Class 12 English Core Paper 1.

CBSE Sample Papers for Class 12 English Core Paper 1

Students who are going to appear for CBSE Class 12 Examinations are advised to practice the CBSE sample papers given here which is designed as per the latest Syllabus and marking scheme as prescribed by the CBSE is given here. Paper 1 of Solved CBSE Sample Paper for Class 12 Englsih Core is given below with free PDF download solutions.

Time Allowed : 3 hours
Maximum Marks : 100

General Instructions

• This paper is divided into three sections: A, B and C. All the sections are compulsory.
• Separate instructions are given with each section and question, wherever necessary. Read these instructions very carefully and follow them faithfully.
• Do not exceed the prescribed Word limit while answering the questions.

SECTION A
READING (30 MARKS)

Question 1.
Read the following passage carefully. (12 Marks)

Cycle of change: Biking communities making the bicycle popular again

1. In 1976, six-year-old Anil Uchil started cycling by renting a bicycle at 25 paise an hour. He got his own road bike when he turned 13, and he cycled everywhere: to school, college and even to work in 1993. He still cycles to work. “It’s healthy, environment-friendly and economical. But the real reason I cycle is because it’s sheer fun,” he says.

2. Earlier this year, PM Narendra Modi, in a speech on environmental crisis, said, “Why don’t we make Sunday cycle day? I am saying that only one day a week; don’t use fuel- driven vehicles.” Internationally, a lot has been done to encourage people to use the bicycle as a primary means of transport. UK’s Cycle to Work scheme offers tax-free bicycles to employees. 45% of people in Copenhagen cycle to work/college. In Brussels (Belgium), Geneva (Switzerland), or San Francisco (USA), it is not uncommon to see top rung corporate executives in three-piece suits cycling their way to office.

3. Cycling, though, has been a part of Indian culture for decades. Apart from people across strata in smaller towns and villages, in cities, mill workers, newspaper delivery boys, milk vendors and bread sellers have always used the bicycle. Today, the resurgent popularity of the bicycle isn’t so much as a practical mode of commuting as it is a way towards fitter lifestyles and eco-friendliness.

4. Around the late 2000s, as the middle and affluent classes took to cycling, internet penetration also grew in India. Many made use of social media to create awareness. Numerous groups on Facebook today help cyclists connect to fellow riders. The shared passion for cycling brings together absolute strangers, building friendships and a sense of community.

5. Jose George, an avid cycling enthusiast and the owner of the cycling store, Haybren Adventures, says, “Riding in a group is always more enjoyable. And you end up riding a lot more.” Usually, the ride distances range from 20 to 80 km, and are held mostly on weekends. Apart from the environmental benefits, cycling is also an effective way to break away from a sedentary lifestyle. “It’s a low-impact exercise where you don’t carry your body weight. The machine does. It’s great stress buster too,” George says.

6. But (while there are eager riders, the lack of infrastructure is a deterrent. Dedicated cycling lanes are still a distant dream. And if the traffic and questionable driving skills of many don’t discourage you, the potholes and gaps between concrete segments might. Another sore point is the derisive attitude of motorists and drivers. Banker and cycling enthusiast Ninad Waghule, 28, says, “Most drivers aren’t considerate towards cyclists. However, if you’re on an expensive cycle and wearing a helmet, you get more respect compared to a regular person commuting to work. It’s a pity.”

7. The cycling culture has also given birth to adventure travel companies that organise cycling trips. From short weekend trips to longer and more arduous (but rewarding) journeys, cycling tours are gaining popularity. CEO Prateek Deo Gupta, a cycling enthusiast, says, “Travelling by cycle, as opposed to a car, shows you know more of the local culture”. Nitin Yadav, co-founder of Delhi-based Cycle It, which focuses solely on cycling trips, says the past four to five months have particularly seen a rise in numbers. Launched last year, Cycle It offers trips on the picturesque Manali to Leh route, and Kumaon, Uttarakhand.

8. American science educator Bill Nye famously said, “There’s something wrong with a society that drives a car to work out in a gym.” Thankfully, in spite of potholed roads and our despicable habit of honking cyclists out of the way, things are changing.

(Source: Manali Shah, Hindustan Times, Mumbai, Oct 08, 2015)

I. On the basis of your understanding of the passage, answer the following questions by choosing the most appropriate option. (1 × 4 = 4 Marks)

(a) Cycling is becoming popular again due to

1. traffic jams.
2. request of the Prime minister.
3. health benefits.
4. reviving Indian culture.

(b) Riding in groups is more beneficial because it helps to :

1. restrict friendships.
2. inculcate sense of kinship.
3. follow the routine of everyday life.
4. none of the above.

(c) Cycling tours are becoming popular because:

1. they are discussed on facebook.
2. they are more satisfying.
3. one can experience more of regional traditions.
4. all the above.

(d) The deterrents to cycling include:

1. Co-operation of the motorists.
2. stress while cycling.
3. non availability of allocated lanes for cyclists.
4. going to the gym regularly.

II. Answer the following questions as briefly as possible. (1 × 6 = 6 Marks)

(e) How has cycling been a part of Indian culture?
(f) What is the difference between the attitude of people of Brussels or Geneva and India to cyclists?
(g) How has the spread of internet helped in promoting cycling?
(h) How have the travel companies benefitted from cycling?
(i) There is a difference in attitude of the drivers to the different cyclists. Explain.
(j) Why does the columnist say that the things are changing?

III. Find words from the passage which mean the same as: (1 × 2 = 2 Marks)

(a) chief (para 2)
(b) sarcastic (para 6)

Question 2.
Read the following passage carefully. (10 Marks)

Don’t be snobbish! Teach your folks the latest technology

1. Quite recently, I observed a young guy in the office cafeteria yelling at his mom because she had called him to ask how to send an audio message through Whatsapp. “Mom, you don’t need to try and be all savvy. Just leave it and make a normal call”, he said, after trying to teach her the commands once, and realising that she’s not getting it. I didn’t like what he said and his tone but it did make me realise and feel guilty about the  several times that even I may have lost patience while helping my parents understand the new technologies. If you are, intentionally or unintentionally, fuelling insecurity and lack of confidence in an elderly person about use of new technologies, you are not doing yourself a favour, because you’ll soon reach that stage yourself.

2. It was not long ago that Orkut became Facebook and BBM became Whatsapp. So it’s not long when these two also become obsolete or die down. The same goes for the operating systems of the various phones and gadgets we use. The fact that most of you so easily adapt to a new platform or gadget is because you are constantly, almost 24X7, using these gadgets. But unlike most of you, people who did not have these gadgets in their hands as constant fixtures have to start from the scratch. Hence, they find it tough and intimidating, and often struggle with the basics. It’s like when they were teaching you ABC. Did they shout at you because you couldn’t frame sentences? So, now that the roles stand reversed and you get to be the teacher, you better treat them with the same love and patience that they showed for you.

3. For those of you who have never experienced the joy of seeing an old person discover the magic of internet, it is a wonderful thing when their eyes light up on discovering that they can message their friends or relatives anywhere in the world and get instant response, for free. They may take ages to type out a coherent sentence, but the moment they click ‘send’, their excitement is incomparable. They may make a lot of mistakes and you may get frustrated or embarrassed but it’s all worthwhile in the end. Remember, holding a smart-phone in your hand doesn’t make you smart. Being able to give back to someone who patiently taught you everything you know in life does.

4. Yes, life is hectic and teaching technology to parents or grandparents isn’t a priority but the little effort of spending an hour every week in making your elders proficient in technology goes a long way in making your own life much easier.

5. While for them, being on social media brings up a new universe to explore joyfully, it also opens several new avenues for you to communicate with your ageing parents. Many young people who were too busy to call their mom or dad often have now taken to regularly chatting with them on Whatsapp. Although I would never agree that chatting or talking on the phone is a sufficient replacement for spending actual, physical time with your elders, it’s still better than not being in touch for days together.

6. So, no more making faces, rolling eyes or being all sarcastic about an elder person struggling with the basics of technology. You may know the software more, but they’ve seen the world more. There’s no comparison.

(Source: Sonal Kalra, Hindustan Times, New Delhi, August 22, 2015)

I. On the basis of your understanding of the passage, answer the following questions by choosing the most appropriate option. (1 × 2 = 2 Marks)

(a) How does the writer suggest that we would be in the same position as the elderly?

1. We will have impatient children
2. Technology gets updated regularly
3. The next generation will speak rudely to us
4. Both (i) and (ii)

(b) The learning process for the elderly with reference to technology would include:

1. taking time to type a understandable message
2. being anxious at their attempts
3. asking about it repeatedly
4. all the above.

II. Answer the following questions as briefly as possible. (1 × 6 = 6 Marks)

(c) What realization did the columnist have after her observation at the cafeteria?
(d) Why does the younger generation pick up technology fast?
(e) What is fascinating about the internet for elderly?
(f) How should we respond to the queries of the elderly regarding technology?
(g) How can teaching technology to the elders in our family make our life easier?
(h) What is the final message of the writer?

III. Find words from the passage which are similar in meaning to the following. (1 × 2 = 2 Marks)

(a) increasing (para 1)
(b) unique (para 3)

Question 3.
Read the following passage carefully. (8 Marks)

In a very short period of time the internet has had a profound impact on the way we live. Since the internet was made operational in 1983, it has lowered both the costs of communication and the barriers to creative expression. It has challenged old business models and enabled new ones. It has provided access to information on a scale never before achievable.

It succeeded because we designed it to be flexible and open. These two features have allowed it to accommodate innovation without massive changes to its infrastructure. An open, borderless and standardized platform means that barriers to entry are low, competition is high, interoperability is assured and innovation is rapid.

The beauty of an open platform is that there are no gatekeepers. For centuries, access to and creation of information was controlled by the few. The internet has changed that and is rapidly becoming the platform for everyone, by everyone.

Of course, it still has a way to go. Today there are only about 2.3 billion internet users, representing roughly 30% of the world’s population. Much of the information that they can access online is in English, but this is changing rapidly. The technological progress of the internet has also set social change in motion. As with other enabling inventions before it, from the telegraph to television, some will worry about the effects of broader access to information—the printing press and the rise in literacy that it effected were, after all, long seen as destabilising. Similar concerns about the internet are occasionally raised, but if we take a long view, I’m confident that its benefits far outweigh the discomforts of learning to integrate it into our lives. The internet and the world wide web are what they are because literally millions of people have made it so. It is a grand collaboration.

It would be foolish not to acknowledge that the openness of the internet has had a price. Security is an increasingly important issue and cannot be ignored. If there is an area of vital research and development for the internet, this is one of them. I am increasingly confident, however, that techniques and practices exist to make the internet safer and more secure while retaining its essentially open quality.

After working on the internet and its predecessors for over decades, I’m more optimistic about its promise than I have ever been. We are all free to innovate on the net every day. The internet is tool of the people, built by the people and it must stay that way.

A. On the basis of your reading of the above passage make notes on it, using headings and sub-headings. Use recognizable abbreviations (wherever necessary—minimum four) and a format you consider suitable. Also supply an appropriate title to it. (5 Marks)

B. Write a summary of the passage in about 80 words. (3 Marks)

SECTION B
ADVANCE WRITING SKILLS (30 MARKS)

Question 4.
Every year on Children’s Day, an exhibition of Science projects is held at the Indira Gandhi Indoor Stadium. Your school has received an invitation from the Education Minister of Delhi inviting the students of your school to visit it. Write a notice in about 50 words informing the students about the display, advising them to go and enjoy it. You are Sunil/Sunita Sahoo, Head Boy/Head Girl Bright Minds Public School, New Delhi. (4 Marks)
OR
Draft a poster informing the readers about hazards of alcoholism in 50 words.

Question 5.
On the approaching Sports’ Day, you realise that many House Flags, batons, badminton racquets, high jump equipment, and many other required by the participants, are in a bad state because of wear & tear. Place an order for all these things along with their numbers to Akram Sports Goods, A-10, Sector-10 Noida, specifying the terms & conditions to get good bargain at a discounted rate for the school. Write this letter as Navtej/Navita, the Sport’s teacher, Navin Public School, 112 Taj Road, Agra. (6 Marks)
OR
Recently you travelled from Bangalore city to Vasco in Vasco Express. To your dismay, you found that the coach was infested with cockroaches. Write a letter to The General Manager, Southern Railways, complaining about the prevailing unhygienic conditions and asking for remedial action. You are Saroj/Saran, 5/31, Bangalore Cantt., Bangalore.

Question 6.
Recent rains and consequent water-logging have increased the risk of malaria and dengue. Write a speech in 150-200 words to be delivered in the morning assembly advising the students on prevention of and protection against these ailments and the steps that the school has taken to prevent mosquito breeding in and around the school. Imagine you are the Principal of the school. (10 Marks)
OR
More industrial production means availability of more goods, better life style, lower prices, more jobs, etc. However, a higher standard of living can be achieved only at a cost and that is, depletion of raw materials and air and water pollution. Write a debate in 150-200 words either for or against the motion—‘Standard of living can be raised, but only at a great cost.’ You are Aseem/Aashima.

Question 7.
Recently, a Car Free Day was organized in Gurgaon and Delhi to encourage the commuters to avail public transport. This was done as vehicles lead to traffic jams, air pollution, road rage and an unhealthy competition in the middle class to own more and newer cars. What are your views on the issue—Private cars or Public transport? Describe them in an article in 150-200 words. You are Sujit/ Sunaina. (10 Marks)
OR
Write a speech to be delivered in the morning assembly in 150-200 words on ‘Delhi: A City of Crime’.

SECTION C
TEXTBOOKS AND EXTENDED READING TEXT (40 MARKS)

Question 8.
Read the following extract carefully and answer the questions that follow : (1 × 4 = 4 Marks)

Those who prepare green wars,
Wars with gas, wars with fire, victory with no survivors,
Would put on clean clothes and walk about With their brothers in the shade, doing nothing.

(a) What are green wars?
(b) How will the few moments of introspection affect the people?
(c) Explain the irony in “Victory with no survivors”.
(d) Name the poem and the poet.

OR
Rich with sprinkling of fair musk rose blooms;
And such too is the grandeur of the dooms
We have imagined for the mighty dead;
All lovely-tales that we have heard or read;
An endless fountain of Immortal drink,
Pouring unto us from the heaven’s brink.

(a) What is the beautiful scene that one sees in the middle of the forest?
(b) Why does the poet call the dooms to be full of grandeur?
(c) Whom does the word ‘mighty dead’ refer to?
(d) Explain ‘Immortal drink’.

Question 9.
Answer any four of the following questions in about 30-40 words each: (3 × 4 = 12 Marks)

(a) Why do you think Aunt Jennifer’s hands are fluttering through her wool? Why is she finding the needle so hard to pull?
(b) Why were a large number of villagers seated on the back benches?
(c) How did the Maharaja manage to save his throne?
(d) Why did Evans drape a blanket round his shoulder?
(e) Why did Bama take half hour to an hour to cover the distance to her home that would normally take only ten minutes?
(f) How did the wizard help Roger Skunk?

Question 10.
Why did Gandhiji consider ‘freedom from fear‘ and a realization that in their own country they can fight for justice was more important than legal and monetary justice for the poor peasants of Champaran? Answer in about 120-150 words. (6 marks)
OR
“The absence of essential value of human compassion, dignity of human life and consideration can be clearly visualized in the ‘Memories of Childhood’.” How far has the meaning of this statement been exemplified in the stories of the two women? Are they close to Malala’s fight for right to education?

Question 11.
How did Dr. Sadao, rise above narrow prejudices of race and country for assisting a human being in need? Discuss. (Word limit 120-150) (6 marks)
OR
By looking at Zitkala-Sa and Bama’s life, one can say that it may take a long time for oppression to be resisted but seeds of rebellion are sowed early in life. Additionally, injustice in any form can have a permanent impact on children too. Justify. (Word limit 120-150) (NCERT)

Question 12.
What forced Griffin to become a bandaged caricature of a man? (Word Limit 120-150) (6 Marks)
OR
What kind of life did Silas lead before coming to Raveloe?

Question 13.
Excessive ambition is behind all that happens in the story. Griffin, devoid of all traces of humanity has become blind in his pursuit. Justify in context of the novel ‘The Invisible Man’. (Word limit 120-150) (6 Marks)
OR
Describe Nancy’s character and her outlook to life in Silas Marner.

ANSWERS

Answer 1.
I.
(a) (iii) health benefits
(b) (ii) none of the above
(c) (iv) all of the above
(d) (iii) non availability of allocated lanes for cyclists.

II. (e) Cycling has always been a part of Indian culture especially among the less affluent in smaller towns and villages. In cities it is used by mill workers, milk vendors newspaper delivery boys and bread sellers. Today it is used as a way to fitter and eco-friendly lifestyles.

(f) In Brussels even the top rung corporate executives prefer cycling to their offices. This is not the case in India.

(g) Spread of Internet has given rise to numerous groups on Facebook that help cyclists connect to fellow riders. Thus a shared passion builds a friendship and a sense of community.

(h) Adventure travel companies have taken to organising short weekend cycling trips to longer and more arduous trips.

(i) Most drivers display derisive attitude towards cyclists unless they are in an expensive cycle with a helmet.

(j) Things are slowly changing as despite the odds more and more people are opting for cycling to keep fit. Social media has proved to be a boon in promoting the culture of cycling.

III. (a) primary (b) derisive

Answer 2.
I. (a) (iv) Both (i) and (ii) (b) (iv) all of the above

II. (c) The columnist realised that she herself may have been impatient with her parents while helping them with new technologies and felt guilty for such treatment.

(d) The younger generation is faster in learning new technologies since they are using them 24 × 7.

(e) The internet opens up a new universe which the elderly explore joyfully. They also love the newer and easier ways of communicating that internet offers.

(f) If elders ask us about the use of technology, we should teach it to them patiently and respectfully.

(g) If we teach technology to the elders of our family, we will be able to have regular chatting or talking with them on phone as we have no time to talk with them regularly face to face.

(h) The final message of the writer is that wre should not make any sarcastic comments if our elders ask us to teach them to use technology, instead we should teach them calmly and respectfully.

III. (a) fuelling (b) incomparable

Answer 3.
A. TITLE: Internet—A Game Changer

NOTES :

1. Features Of Internet

(a) Flexible & open
(b) Standardised platform
(c) High Compttn.
(d) Rapid innovation.

2. Global Penetration

(a) Used by 30% of populn.
(b) English-major language.

3. Positive Impact

(a) Agent of social change
(b) Enable new busi. models
(c) Lowered commun. costs
(d) Aids creative innovation

4. Areas of concern

(а) Insecure platform v open
(b) Need to put checks for greater safety.

B. SUMMARY

Internet is an open and flexible platform. It is standardised. The competition is high and is open to rapid innovation. About 30% of the world population is internet user. Though the access is in English but this is also changing. It has positively impacted society as it has triggered great social change. It has also enabled new business models. Besides lowering communication costs it has aided creative innovation. Still it is not without drawbacks. The greatest one being that due to its openness it is too insecure. There is a need to create checks and practices which will lend it greater degree of safety.

Answer 4.

Answer 5.
Navin Public School
112 Taj Road, Agra
30th Sep, 20XX

The Manager
Akram Sports Goods
A-10, Sector 10, Noida

Sub: Order for Sports Goods

Dear Sir,

Our school is going to host its Annual Sports Day on 18 October, 20xx. With regard to this, we would like to place an order for certain sports equipment.

The set specifications of the order are as under :

Since our association with you is a long one, we would like a discount of 25% on the above order. You are requested to arrange for the goods to be delivered by 8 October, 20xx. Kindly note that the damaged goods will be returned for replacement. Payment would be made by cheque at the time of delivery.

Yours sincerely
Navtej
H.O.D., Sports Department

OR

5/31, Bangalore Cantt.
Bangalore
7th September, 20xx
The General Manager
Southern Railways

Sub: Unhygienic Condition in Rail Coaches

Dear Sir/Madam

Last month I took the Vasco Express from Bangalore on a business related matter. After I settled myself and my luggage thinking of getting a good night’s rest, I was dismayed and disgusted to see cockroaches creeping out of the seat. I myself spotted not less than fifteen or twenty. I could not sleep the entire night fearing that they may crawl over me while I was sleep.

Sir, my mind is full of questions. Is it not the customer’s right to have clean and pest-free compartment as they pay for the travel? Railways need to improve the hygienic conditions of the coaches in order to improve their own reputation and the travel experience of their customers.

Yours sincerely
Saroj

Answer 6.
Good morning, respected principal, teachers and students! I take the opportunity in this morning assembly to address you on an important health issues. As you all are aware the recent heavy rains have caused widespread waterlogging and have increased the risk of malaria and dengue. I am sure you know that both these diseases are caused by mosquitoe bites and once contracted can take a toll on your health. Here are a few tips to keep mosquitoes at bay.

• Wear full sleeve clothes.
• Wear trousers instead of shorts and skirts.
• Use mosquito repellant creams and patches.

On our part we have arranged fumigation of all rooms, nooks and corners by professionals. One bottle of mosquito spray has been kept in each class to use as and when required. All drains in and around the school have been cleaned and disinfected.

I hope you will take care of your health and cooperate in creating mosquito-free surroundings.

Thank you.

OR

Esteemed judges I, Aseem stand before you to debate for the motion. Standard of living can be raised but only at a great cost. We are living in an era of consumerism, which dictates our definition of ‘standard of living’. In a nutshell if you have more goods and more and more of the same goods, you are perceived as having a high standard of living. For example, car owners are seen as having a higher standards than those who own scooters. Likewise a person owning three cars is seen with more respect and admiration than the one having just one. But raising of the so-called standard of living entails a great toll on our natural resources. More trees need to be cut to have bigger and better houses and furniture. More animals need to be butchered to satisfy our taste for exotic meats. These are but a few examples. Our consumerist attitude may deplete the earth in the near future. So the need of the hour is to adopt a minimalistic lifestyle thereby saving the earth’s resources.

Thank you.

Answer 7.
Private cars or public Transport? By: Sujit

The Delhi government recently announced Car-free days in a bid to decrease congestion on roads and encourage commuters to use public transport. The number of cars on Delhi roads is on the rise owing to the rising purchasing power of the middle class coupled with the desire to compete with others. Hardly do they realise that how much congestion and pollution is caused due to this trend.

The advantages of using private cars are that they are convenient and comfortable and give the users a great degree of autonomy. The disadvantages of using private card are that they result in traffic jams, air pollution and accidents. Though public transport has some drawbacks, yet we should try to use public transport as much as possible instead of our private cars. DTC buses are unreliable and unsafe especially for women who sometimes suffer eve-teasing while travelling in them. They are overcrowded too. Delhi Metro is a better alternative as it is punctual, safer for women and more secure. There is a need to increase the frequency of DTC buses and metro trains to make public transport more appealing. Autos should run only by the meter and not should not over charge.

OR

Respected Principal, teachers and my dear friends!

Today I am going to express my views on the topic ‘Delhi: A City of Crime’ and hope my views will be appreciated by you.

Delhi has become notorious for its crime rate—robberies in the day time, murders of senior citizens in crowded colonies, kidnappings from main roads and rapes in moving cars. With the police dragging its feet in catching the wrongdoers and the courts’ lackadaisical attitude in passing judgement, criminals are encouraged to continue their nefarious activities. Matters are not helped when highly placed officials and politicians use their influence upon the guilty. The contrast between the wealthy and the underprivileged is growing, and with the open display of wealth of the former, the latter feel crime is the shortest way to achieve the same goals. Movies romanticize the bad and the ugly side of life, adding fuel to the already growing fire. People themselves break laws by not verifying their servants or tenants or by turning a blind eye to wrongdoings.

The city has acquired a bad reputation. Where once only selected areas were considered unsafe, now the whole city is under attack.

The government needs to take strict action against recalcitrant police officers and those who block the course of justice. Judgement in criminal cases must be swift and harsh. People must realise that they also have the responsibility of keeping crime at bay. It is only when everyone works together that we can make Delhi a worthwhile place to live in.

Thank you.

Answer 8.

(a) ‘Green wars’ are all activities which harm nature and environment.
(b) While introspecting, the poet hopes that man will be able to see their mindless activities which are harming nature. They may change their goals and means to achieve their needs thus bringing more peace in their lives.
(c) It is ironical that when wars are won there are no survivors to celebrate the victory.
(d) The poem is ‘Keeping Quiet’. The poet is Pablo Neruda.

OR

(a) One sees the musk rose blooming in the middle of the forest.
(b) The stories of the death of the mighty heroes in the past have been described with great grandeur. Hence the poet speaks about them admiringly.
(c) ‘Mighty dead’ refers to the great and powerful inspiring heroes who are now dead.
(d) The things of beauty are a source of eternal pleasure and relaxation to man. Thus the immortal drink, an elixir, never dries up.

Answer 9.
(a) Aunt Jennifer’s fluttering fingers indicate her terrorised and tortured state of mind. The uncle’s wedding ring has burdened her soul and personality so much that she finds even a needle hard to handle.

(b) It was the last day of French lessons in M. Hamel’s classroom. The German order had forbidden the learning of French from the next day. Only German would be spoken in Alsace. The villagers had come to attend the last French lesson to pay their respect to their teacher who had spent forty years in teaching French.

(c) The Maharaja had refused the British official. In doing so he ran a great risk as his kingdom could be annexed. To make up to the British official he sent 50 rings to the official’s wife who instead of choosing one or two accepted all the 50 rings as a gift. The Maharaja paid a heavy sum but managed to save his throne.

(d) Evans draped on a blanket around his shoulder on the pretext of his cell being cold. In fact, beneath it he changed his clothes that McLeery brought for him.

(e) Ori her way back home Bama was captivated by the many entertaining people and activities of the market. She found the snake charmer, the performing monkey to name a few very engrossing. Hence the ten minute walk stretched to thirty minutes.

(f) The wizard helped Roger Skunk by substituting the awful smell of the skunk with the beautiful fragrance of roses. In doing so the wizard helped Roger Skunk immensely as now he was happily accepted by his friends.

Answer 10.
Gandhiji believed that the 25% refund amount was insignificant for the peasants. What was more vital was that for the first time the farmers had won a court case against the British. The farmers had gained confidence and courage while the British complacency had received a rude jolt. This episode released the farmer from the shackles of fear of the British. Hitherto the farmers had lived in complete subjection to the British but with losing the court case the British had to part with their prestige and also some of their money. Gandhiji saw this as a victory of truth. Also Gandhiji’s dream that Indians should live on their land freely and fearlessly was realized for the first time. He believed that if minds were freed of fear, independence would not be far behind.
OR
Both Zitkala-sa and Bama were victims of discrimination. While the farmer suffered racist discrimination, Bama suffered the caste-based discrimination in the form of untouchability. They suffered great atrocities. The whites in the Carlisle school sought to erase her identity by teaching her western ways and manners. Her long hair was shingled. This was forbidden in her Indian culture; She was made to wear tight dresses which she found immodest. Likewise Bama learnt from her brother that she was Dalit and hence untouchable. Bama and Zitkala-sa both experienced painfully how prejudice and discrimination can deprive human beings of compassion, consideration and humanity. Malala has fought for education for girls in her own country, Afghanistan. She too must have experienced the indignities humans can commit due to lack of education.

Answer 11.
After Sadao decided to help the wounded American soldier, he experienced a conflict between his sense of patriotism and sense of professional duty. He was in a dilemma—if he abandons the American he would be doing a disservice to his profession as a surgeon; if he helped him he would be betraying his country. He resolves this dilemma by choosing humanity over considerations of race. He also has to overcome his personal hatred of Americans whom he had come to loathe during his stay in America. In the end Sadao rises above all these narrow considerations and upholds humanity and his professional duty to serve humanity.
OR
The experiences and life of Bama and Zitkala-sa exemplify that oppression and injustice doesn’t go unnoticed even by children. Zitkala-sa experienced extreme blows to her sense of identity and self-esteem. Similarly a young Bama realized that she was an untouchable. Her anger at the upper caste who subjugated them and yet used them shamelessly is brought out in Bama’s account. In the throes of mental agony it is her brother who advises her to educate herself well so as to break the shackles of untouchability. Zitkala-sa and Bama grew up to be champions of equality. By writing about their experiences of societal discrimination they took to creating an equal, discrimination free society by creating awareness among their readers.

Answer 12.
Griffin was a genius, a student of science. He dreamed of becoming invisible so as to become all powerful. His untiring experiments made him realize this evil dream. Ironically invisibility proved very inconvenient to Griffin: People knocked into him on roads, the food and drink in his digestive tract could be spotted since it was visible. Moreover he could not bear the chill of England. Now he longed to reverse the experiment. To brave the cold he put on warm clothes, bandaged his face, stuck a fake pink nose on his face in order to appear normal. Thus his unnatural ambition reduced him to a caricature of a man physically but also degraded him morally and spiritually.
OR
Before coming to Raveloe, Silas Marner lived in a town called Lantern Yard. He was a weaver and a religious man. He was friendly and popular so that people loved him. He was engaged to Sara. William Dane was his trusted friend. Silas often suffered from epileptic fits. During these fits he lost all consciousness. His friend thought that he was possessed by Satan. During one such fit, William taking advantage of his unconscious state framed him as a thief. Silas was subsequently expelled on the charge of stealing money. He was embittered and lost all faith and trust. In such a mental state he arrived at Raveloe.

Answer 13.
In his pursuit of invisibility Griffin gradually loses all traces of humanity. He became isolated and hated people. His treatment with Marvel highlights his predilection for violence and abuse. He ill treats his father too by stealing his money. His father, commits suicide. Yet Griffin does not feel any remorse. He commits a burglary in Mr. Bunting’s house. He also harasses Mrs Hall many times by his rudeness and carelessness. Later he misuses Dr. Kemp who he sees as his enemy and declares to kill him. Thus Griffin is totally blinded by his pursuit of power and becomes a maniac.
OR
Nancy is a beautiful and charming girl from a rich family of Raveloe. She is caring. Godfrey loves and later marries. She has a strict moral upbringing and regards Godfrey’s flaws of character with disapproval. Yet she can’t help being flattered by Godfrey’s attention. Nancy carries herself gracefully in a lady like manner yet she is aware about her typical rural traits: her coarse hands betray her sophisticated manners. There is no denying her that physical beauty, height and upright posture and above all her moral sense were praiseworthy. After marriage, Nancy is stopped by her moral sense to adopt a child but she makes up to Godfrey for this lack in other ways. When she learns that Eppie is Godfrey’s daughter, she is moved by love and sympathy.

We hope the CBSE Sample Papers for Class 12 Englsih Core Paper 1 help you. If you have any query regarding CBSE Sample Papers for Class 12 English Core Paper 1, drop a comment below and we will get back to you at the earliest.

These Sample papers are part of CBSE Sample Papers for Class 12 Biology. Here we have given CBSE Sample Papers for Class 12 Biology Paper 2.

CBSE Sample Papers for Class 12 Biology Paper 2

Students who are going to appear for CBSE Class 12 Examinations are advised to practice the CBSE sample papers given here which is designed as per the latest Syllabus and marking scheme as prescribed by the CBSE is given here. Paper 2 of Solved CBSE Sample Paper for Class 12 Biology is given below with free PDF download solutions.

Time Allowed: 3 hours
Maximum Marks: 80

General Instructions:

1. There are total 26 questions and five sections in the question paper. All questions are compulsory.
2. Section A contains question number 1 to 5, Very Short Answer Type Questions of one mark each.
3. Section B contains question number 6 to 10, Short Answer Type Questions of two marks each.
4. Section C contains question number 11 to 22, Short Answer Type Questions of three marks each.
5. Section D contains question number 23, Value Based Question of four mark.
6. Section E contains question number 24 to 26, Long Answer Type Questions of five marks each.
7. There is no overall choice in the question paper, however, an internal choice is provided in one question of two marks, one question of three marks and all three questions of five marks. An examiner is to attempt any one of the question out of the two given in the question paper with the same question number.
8. No. of printed pages are three.

SECTION-A

Question 1.
Observe the pedigree chart and answer the following questions:
(a) Identity whether the trait is sex linked or autosomal.
(b) Give an example of a disease in human beings which shows such a pattern of inheritance.

Question 2.
Identify the reason for the selection of DNA polymerase from Thermus aquaticus for Polymerase Chain Reaction

Question 3.
Govt, of India has raised the marriageable age of females to 18 yrs and of males 21 yrs. Suggest any two measures adopted by the government for the purpose.

Question 4.
Thymus of a new born child was degenerating right from birth due to genetic disorder. Predict its two impacts on the health of the child.

Question 5.
Give an example of a chromosomal disorder caused due to non-disjunction of autosomes

SECTION-B

Question 7.
A single pea plant in your kitchen garden produces pods with seeds, but the individual papaya plant does not. Explain.

Question 8.
Suggest four important steps to produce a disease resistant plant through conventional plant breeding technology.

Question 9.
Name a genus of baculovirus. Why are they considered good biocontrol agents?

Question 10.
Explain the relationship between CFCs or Ozone in the stratosphere.

OR

Why are sacred groves highly protected?

SECTION-C

Question 11.
Why is breast feeding recommended during the initial period of an infant’s growth? Give reasons.

Question 12.
Give an example of an autosomal recessive trait in humans. Explain its pattern of inheritance with the help of a cross.

Question 13.
Describe the experiment that helped Louis Pasteur to dismiss the theory of spontaneous generation of life

Question 14.
Plant breeding technique has helped sugar industry in North India. Explain how.

Question 15.
Suggest and describe a technique to obtain multiple copies of a gene of interest in vitro.

Question 16.
What is GMO? List any five possible advantages of a GMO to a farmer.

Question 17.
During a school trip to ‘Rohtang Pass’, one of your classmate suddenly developed “altitude sickness”. But, she recovered after sometime.
(a) Mention one symptom to diagnose the sickness.
(b) What caused the sickness?
(c) How could she recover by herself after sometime?

Question 18.
How has RNAi technique help to prevent the infestation of roots into tobacco plants by nematode Meloidegyne incognitia?

Question 19.
“In a food chain, a trophic level represents a functional level, not a specie.” Explain. 3

OR

(a) Name any two places where it is essential to install electrostatic precipitators. Why is it required to do so?
(b) Mention one limitation of the electrostatic precipitator

Question 20.
Prior to a sports event, blood and urine sample of sports person are collected for drug tests.3
(a) Why is there a need to conduct such tests?
(b) Name the drugs the authorities usually look for.
(c) Write the generic names of two plants from which these drugs are obtained.

Question 21.
Describe the experiment that helped to demonstrate the semi conservative mode of DNA replication.

Question 22.
Given below is a list of six micro-organisms. State their usefulness to humans:
(a) Nucleopolyhedrovirus
(b) Saccharomycs cerebisiae
(c) Monascus purpureus
(d) Trichoderma polysporum
(e) Penicillium notatum
(f) Propionibacterium sharmanii

SECTION-D

Question 23.
Reproductive and Child Flealthcare (RCH) programme are currently in operation. One of the majof tasks of these programmes is to create awareness amongst people about the wide range of reproduction related aspects. As this is important and essential for building a reproductively healthy society.
(a) “Providing sex education in schools is one of the ways to meet this goal.” Give four points in support of your opinion regarding this statement.
(b) List any two ‘indicators’ that indicate a reproductively healthy society.

SECTION-E

Question 24.
(a) Explain the post-pollination events leading to seed production in angiosperms.
(b) List the different types of pollination depending upon the source of pollen grains.

OR

(c) Briefly explain the events of fertilisation and implantation in an adult human female.
(d) Comment on placenta as an endocrine gland.

Question 25.
(a) How are the following formed and involved in DNA packing in a nucleus of a cell? 5

• Histone octomer
• Nucleosome
• Chromatin

(b) Differentiate between Euchromatin and Heterochromatin.

OR

Explain the role of lactose as an inducer in a lac operon

Question 26.
(a) Why should we conserve biodiversity? How can we do it?
(b) Explain the importance of biodiversity hot spots and sacred groves.

OR

(a) Represent diagrammatically three kinds of age-pyramids for human populations.
(b) How does an age pyramid for human population at given point of time help the policy makers in planning for future

Answers

SECTION-A

Answer 1.

(a) Sex-linked.

(b) Haemophilia/Colourblindness.

Answer 2.
Identify the reason for the selection of DNA polymerase from Thermus aquaticus for Polymerase Chain Reaction.

Answer 3.
Incentives given to couples with small families/media publicity – posters of happy couples with two children (slogan-Hum Do Humare Do)/Motivate to promote smaller families by using contraceptive methods. (Any two)

Answer 4.
Thymus provides micro-environment for the development and maturation of T-lymphocytes; its degeneration will weaken the immune system so the child will be prone to frequent infections.

Answer 5.
Down’s Syndrome.
SECTION-B

Answer 6.
Pea: Flowers of pea plants are bisexual, monoecious / self pollinated (to produce pods with viable seeds.

Papaya: Dioecious plant/unisexual plant bearing male and female flowers on separate plants, unable to produce viable seeds as there is no cross pollination/it could be a male plant which is unable to produce fruit and seeds.

Answer 7.
Stop codon: does not code for any amino acid/terminates the synthesis of polypeptide chain. Unambiguous codon: one codon codes for one amino acid only
Degenerate codon: some amino acids are coded by more than one codon
Universal codon: genetic code is same for all organisms (bacteria to humans)

Answer 8.
Steps for producing disease resistant plants:

1. Screening of germplasm (for resistance sources)
2. Hybridization of selected parents !
3. Selection and evaluation of hybrids
4. Testing and release of new varieties

Answer 9.
Nucleopolyhedrovirus.
Species specific, narrow spectrum insecticidal application, no negative impact on non target organisms.

Answer 10.
UV rays act on CFC’s, release Cl atoms, which act on ozone to release O₂, resulting in ozone layer depletion/causing ozone hole.

 OR

Sacred groves are highly protected because of religious and cultural traditions, refuge for large number of rare and threatened plants/ecologically unique and biodiversity rich regions.

SECTION-C

Answer 11.
Colostrum, rich in nutrients, rich in antibodies/rich in IgA/provide passive immunity/provides :immunity to new born/helps to develop resistance in new born/readily available for new born? hygienic/develops a bond between mother and child.

Answer 12.
Sickle cell anaemia/Phenylketonuria/Thalassemia/O Blood group /Non-rolling of tongue / fused or attached ear lobes / inability to taste PTC (phenyl thiocarbamide).

Similar cross can be considered for any other trait mentioned above.

Answer 13.

Two pre sterilised flasks with killed yeast, one sealed, other open to air, differential growth of life in two flasks/life was found only in open flask. The given diagram can be considered in lieu of above explanation.
Life comes from pre-existing life (it came from air entering the flask)/proved the theory of biogenesis.

Answer 14.
Two species (Saccharum barberi and Saccharum officinarum) were crossed to get sugarcane varieties with high yield/thick stem/high sugar content/ability to-grow in North India.

Answer 15.
PCR/Polymerase Chain Reaction.
Separation/ denaturation of two strands of two dsDNA, using two sets of primers / small chemically synthesised oligonucleotides complementary to regions of DNAand (thermostable) DNA polymerase/Taq polymerase, extension of the primers, by enzyme using nucleotides replicates the DNA and if the process of replication is repeated many times, multiple copies of DNA are produced.
The following diagram can be considered in lieu of the explanation.

Answer 16.
1. Plants/bacteria/ fungi/ animals whose genes have been altered by manipulation.
2. Tolerance to abiotic stresses/like cold/drought/salt/heat, reduced reliance on chemical pesticides/pest resistant crops, reduce post harvest losses, increased efficiency of mineral usage by plants, enhanced nutritional value, to create tailor made plant.

Answer 17.
(a) Nausea/fatigue/heart palpitation
(b) Low atmospheric pressure at high altitude, body deprived of O₂.
(c) Increase in RBC, decreases binding capacity of haemoglobin, increased breathing rate, get acclimatised.

Answer 18.
Using Agrobacterium vectors, nematode specific genes introduced into host plant, produced sense antisense RNA in host cells, ds RNA – initiated RNAi, silenced specific mRNA of nematode, parasite could not survive in transgenic host.

Answer 19.
Position of a species in any trophic level is determined by the function performed by that mode of nutrition of species in a particular food chain. A given species may occupy more than one trophic level in the same ecosystem (in different food chains) at the given time. If the function of the mode of nutrition of species changes its position shall change in the trophic levels, same species can be at primary consumer level in one food chain and at secondary consumer level in another food chain in the same ecosystem at the given time.

OR

(a) Thermal power plants/smelters/ other particulate matter releasing industries.
To remove particulate matter (Any two)
(b) Very small particulate matter/less than 2.5 micrometres are not removed/velocity of air between plates must be low enough to allow the dust to fall/cannot work without electricity.

Answer 20.
(a) To detect drug abuse/use of banned drugs/use of cannabinoids/anabolic steroids/narcotic analgesic/diuretics/hormones/drugs used to accelerate performance / increase muscle strength/bulk/promote aggressiveness/to ensure fair game.
(b) Cannabinoids/cocaine/coca alkaloid / coke /crack/ hashish /charas/ganj a /hemp plant extract.
(c) Cannabis/Atropa/Erythroxylum/Datura. (Any two)

Answer 21.
Matthew Meselson and Franklin Stahl grew E.coil in ¹⁵NH₄C1 for many generations to get ¹⁵N incorporated into DNA. Then the cells are transferred into ¹⁴NH₄C1. The extracted DNA are centrifuged in CsCl and measured to get their densities, DNA extracted from the culture after one generation (20 minutes), showed intermediate hybrid density, DNA extracted after two generations (40 minutes) showed light DNA and hybrid DNA.

A correctly labelled diagrammatic representation in lieu of the above explanation of experiment to be considered.

Answer 22.
(a) As bio control agents / species specific / narrow spectrum insecticidal application / no negative impacts on plants / mammals / birds / fish / non target insects / Integrated Pest Management.
(b) Used in bread making/brewing industry/ethanol/CO, production
(c) Cholesterol lowering agent/competitively inhibiting the enzyme responsible for synthesis of cholestrol
(d) Produces cyclosporin-A/immuno suppressive agent
(e) Produces antibiotic penicillin
(f) Produces large holes in swiss cheese/products large amount of CO₂ in swiss cheese.

SECTION-D

Answer 23.
(a)

• Provide right information to the young so as to discourage children from believing in myths and
• misconception about sex related aspects.
• Proper information about reproductive organs
• Proper information about adolescence and related changes
• Safe hygienic practices
• STDs/AIDS
• Available birth control options
• Care of pregnant mothers
• Post natal care
• Importance of breast feeding
• Equal opportunities for male and female child
• Awareness of problems due to uncontrolled population growth
• Sex abuse
• Sex related crimes (Any four)

(b) Better awareness about sex related matters/increase in number of assisted deliveries/better post natal care/decrease in IMR (Infant Mortality Rate)/decrease MMR(Matemal Mortality Rate)/increase in number of couples with small families/better detection and cure of STDs/ overall increased medical facilities for sex related problems/total well being in all aspects of reproduction/physical-behavioural-social /physically and functionally normal reproductive organs/normal emotional and behavioural interaction among all sex related aspects. (Any two)

SECTION-E

Answer 24.
(a) Pollen pistil interaction, germination of pollen tube that carries two male gametes, double
fertilization / syngamy and triple fusion, development of endosperm, development of embryo, maturation of ovule into seed.
(b) Autogamy/self pollination/Geitonogamy Xenogamy/cross pollination

OR

(a) Fertilization:

• Sperm comes in contact and enters the secondary oocyte
• Activates / induces secondary oocyte to complete meiosis II leads to formation of ovum/ootid
• The haploid nucleus of sperm and that of ovum fused to form a diploid zygote completing the process of fertilization

Implantation:

• Trophoblast layer of blastocyst attaches to the endometrium (of the uterus)
• The uterine cells divide rapidly and cover the blastocyst,
• The blastocyst becomes embedded in the endometrium and the implantation is

Answer 25.
(a)
1. Eight molecules of (positively charged basic proteins called) histones are organised to form histone octamer.
2. Negatively charged DNA wrapped around positively charged histone octamer to give rise to nucleosome
3. Nucleosome constitute the repeating unit of a structure called chromatin

(b)

OR

Lactose/inducer binds with repressor protein, inactivates it, frees operator gene, RNA polymerase freely move over structural genes/RNA polymerase access to the promoter, transcribing to, lac mRNA, which on translation, produce transacetylase, permease, β-galactosidase.
The following diagram to be considered in lieu of above explanation.

Answer 26.
(a)
(1) Narrowly utilitarian-related examples like derive economic benefits from nature food (cereals, pulses, fruits)/firewood/fibre/construction materials/industrial products (tannins, lubricants, dyes, resi’ns, perfumes) / product of medicinal importance/drugs.

• Broadly utilitarian — 20% of total 0₂ from Amazon forests / pollination / aesthetic pleasures.
• Ethical — millions of species (plants, animals, microbes) share this planet/we need to realise that every species has an intrinsic value (even if it may not have any economic value to us)/we have a moral duty to care for their well being and pass on our biological legacy to future generations.

(2)

• In situ conservation / biosphere reserves/ national parks / sanctuaries / sacred groves.
• Ex situ conservation/zoological parks /botanical gardens/wild life safari parks/cryopreservation/seed banks/tissue culture (eggs in vitro).

(b) Hot spots – regions with high level of species richness, high degree of endemism Sacred groves – tracts of forest containing tree/wildlife were venerated, and given total protection/to protect last refuges for a large number of rare and threatened plants.

OR

(b) Planning of health/ education/transport/ infrastructure/finance/food/employment can depend on the age-pyramid analysis of a population. (Any two explanations)

We hope the CBSE Sample Papers for Class 12 Biology Paper 2 help you. If you have any query regarding CBSE Sample Papers for Class 12 Biology Paper 2, drop a comment below and we will get back to you at the earliest.

CBSE Sample Papers for Class 12 Maths Paper 6 are part of CBSE Sample Papers for Class 12 Maths. Here we have given CBSE Sample Papers for Class 12 Maths Paper 6.

CBSE Sample Papers for Class 12 Maths Paper 6

Students who are going to appear for CBSE Class 12 Examinations are advised to practice the CBSE sample papers given here which is designed as per the latest Syllabus and marking scheme as prescribed by the CBSE is given here. Paper 6 of Solved CBSE Sample Paper for Class 12 Maths is given below with free PDF download solutions.

Time: 3 Hours
Maximum Marks: 100

General Instructions:

• All questions are compulsory.
• Questions 1-4 in section A are very short answer type questions carrying 1 mark each.
• Questions 5-12 in section B are short answer type questions carrying 2 marks each.
• Questions 13-23 in section C are long answer I type questions carrying 4 marks each.
• Questions 24-29 in section D are long answer II type questions carrying 6 marks each.

SECTION A

Question 1.
If A is a matrix of order 2 x 3 and B is of order 3 x 4, what is the order of (AB)’?

Question 2.
If \(\vec { P }\) is a unit vector and \(\left( \vec { x } -\vec { P } \right) \cdot \left( \vec { x } +\vec { P } \right) =80\), then find the value of \(\left| \vec { x } \right|\).

Question 3.
Evaluate \(\int { \sqrt { \frac { x }{ 1-{ x }^{ 3 } } } } dx\)

Question 4.
Find the point at which tangent to the curve y = x² makes an angle of 45° with x-axis.

SECTION B

Question 5.
Express the matrix \(A=\begin{pmatrix} 3 & 5 \\ 1 & -1 \end{pmatrix}\) as the sum of symmetric and skew symmetric matrix.

Question 6.
If x^y = y^x, find \(\frac { dy }{ dx }\)

Question 7.
Verify Rolle’s theorem for f(x) = sin 2x in [0, \(\frac { \pi }{ 2 }\)] and find the value of ]0, \(\frac { \pi }{ 2 }\)[

Question 8.
Discuss continuity of the function at x = 0

Question 9.
Find the coordinate of point of intersection of lines

Question 10.
If P(A) = \(\frac { 1 }{ 4 }\), P(A | B) = \(\frac { 1 }{ 2 }\), P(B | A) = \(\frac { 2 }{ 3 }\) then find P(B).

Question 11.
If 3 tan^-1x + cot^-1x = π then find the value of x.

Question 12.

SECTION C

Question 13.

Question 14.

Question 15.

Question 16.

Question 17.

Question 18.
Solve the differential equation (1 + y²) dx = (tan^-1 y – x) dy ; y(0) = 0

Question 19.
The scalar product of the vector \(\hat { i } +\hat { j } +\hat { k }\) with a unit vector along the sum of vectors \(2\hat { i } +4\hat { j } -5\hat { k }\) and \(\lambda \hat { i } +2\hat { j } +3\hat { k }\) is equal to one. Find the value of λ.

Question 20.

Question 21.
A and B throw a die alternately till one of them gets a 5 and wins the game. F ind their respective probabilities of winning if A starts the game. Why gambling is not a good way of earning money?

Question 22.
In a bolt factory, machine A, B and C manufacture respectively 25%, 35% and 40% of the bolts. of their output, 5%, 4% and 2% are respectively defective bolts. A bolt is drawn at random from the total production and is found to be defective. Find the probability that it is manufactured by machine B.

Question 23.
A binary operation * on the set {0, 1, 2, 3, 4, 5} is defined as

Show that zero is the identity element for. this operation and each non-zero element ‘a’ of the set is invertible with 6 – a being the inverse of a.

SECTION D

Question 24.

Question 25.
Prove that the radius of the right circular cylinder of greatest curved surface area which can be inscribed in a given cone is half of that of the cone.
OR
An open box with square base is to be made out of a given quantity of sheet of area a² sq.units. Show that the maximum volume of the box is \(\frac { { a }^{ 3 } }{ 6\surd 3 }\) cubic units.

Question 26.
Using integration find the area bounded by the lines x + 2y = 2, y – x = 1 and 2x + y = 7.
OR
Find the area of the region in the first quadrant enclosed by the y-axis, the line y = x and the circle x² + y² = 32 using integration.

Question 27.
A dealer wishes to purchase a number of fans and sewing machines. He has only ₹ 5760 to invest and has space for at most 20 items. A fan cost him ₹ 360 and a sewing machine ₹ 240. On selling he get a profit of ₹ 22 on a fan and ₹ 18 on a sewing machine. Assuming that he can sell all the items that he store, how should he invest his money in order to maximize profit? Formulate this as L.P.P. and solve it graphically.

Question 28.
Find the image of the point (1, 2, 3) in the plane x + 2y + 4z = 38.
OR
Find the equation of the plane passing through the points A(3, -1, 2), B (5, 2, 4) and C(-1, -1, 6). Also find the distance of the point P(6, 5, 9) from the plane.

Question 29.
Show that the differential equation x dy – y dx = \(\sqrt { { x }^{ 2 }+{ y }^{ 2 } }\) dx is homogeneous and hence solve it.

Solutions

Solution 1.
A = [a_ij]_2×3
B = [b_ij]_3×4
Order of AB = 2 x 4
Order of (AB)’ = 4 x 2

Solution 2.

Solution 3.

Solution 4.
Let the point is (x, y)
y = x²

Solution 5.

Solution 6.

Solution 7.

Solution 8.

Solution 9.

Solution 10.

Solution 11.

Solution 12.

Solution 13.

Solution 14.

Solution 15.
y = sinpt
x = sint

Solution 16.

Solution 17.

Solution 18.

Solution 19.

Solution 20.

Solution 21.

Solution 22.
Let E₁ is the event the bolt is manufactured by machine A
E₂ is the event the bolt is manufactured by machine B
E₃ is the event the bolt is manufactured by machine C
A is the event bolt drawn is defective

Solution 23.

Solution 24.

Solution 25.

Solution 26.
x + 2y = 2 ……. (1)
y – x = 1 …… (2)
2x + y = 7 ……. (3)
From (1) and (2), (0, 1)
From (2) and (3), (2, 3)
From (1) and (3), (4, -1)

Solution 27.
Let dealer purchases x fans and y sewing machines.
Objective function is maximize profit Z = 22x + 18y

Solution 28.

Solution 29.

We hope the CBSE Sample Papers for Class 12 Maths Paper 6 help you. If you have any query regarding CBSE Sample Papers for Class 12 Maths Paper 6, drop a comment below and we will get back to you at the earliest.

These Sample papers are part of CBSE Sample Papers for Class 12 Biology. Here we have given CBSE Sample Papers for Class 12 Biology Paper 1.

CBSE Sample Papers for Class 12 Biology Paper 1

Students who are going to appear for CBSE Class 12 Examinations are advised to practice the CBSE sample papers given here which is designed as per the latest Syllabus and marking scheme as prescribed by the CBSE is given here. Paper 1 of Solved CBSE Sample Paper for Class 12 Biology is given below with free PDF download solutions.

Time Allowed: 3 hours
Maximum Marks: 80

General Instructions:

1. There are total 26 questions and five sections in the question paper. All questions are compulsory.
2. Section A contains question number 1 to 5, Very Short Answer Type Questions of one mark each.
3. Section B contains question number 6 to 10, Short Answer Type Questions of two marks each.
4. Section C contains question number 11 to 22, Short Answer Type Questions of three marks each.
5. Section D contains question number 23, Value Based Question of four mark.
6. Section E contains question number 24 to 26, Long Answer Type Questions of five marks each.
7. There is no overall choice in the question paper, however, an internal choice is provided in one question of two marks, one question of three marks and all three questions of five marks. An examiner is to attempt any one of the question out of the two given in the question paper with the same question number.
8. No. of printed pages are three.

SECTION-A

Question 1.
Recently chikungunya cases were reported from various parts of the country. Name the vector responsible for it.

Question 2.
Why cashew is referred to as false fruit?

Question 3.
Name two animals that have become extinct due to over-exploitation.

Question 4.
What forms the backbone of a polynucleotide strand of a nucleic acid?

Question 5.
How is the presence of cyanobacteria in the paddy fields beneficial to rice crop?

SECTION-B

Question 6.
Why should a bisexual flower be emasculated and then bagged prior to artificial pollination in hybridisation programmes?

Question 7.
How does CuT act as an effective contraceptive for human females?

Question 8.
How and why is the bacterium, Thermus aquaticus, useful in rDNA technology?

Question 9.
Differentiate between predation and competition.

Question 10
Highlight any four advantages of genetically modified or transgenic animals.

SECTION-C

Question 11.
Draw a diagram of a mature embryo of grass and label six parts in it.

OR

Describe the structure of a microsporangium of an angiosperm along with its diagram.

Question 12.
Who proposed chromosome theory of inheritance? Point structure of Microsporangium
out any two similarities between the behaviour of genes and that of chromosomes.   

Question 13.
A person is suffering from Amoebiasis. Mention the pathogen that causes it and one organ of the body that gets affected. Give three symptoms and one mode of its transmission.

Question 14.
How do organisms manage with the stressful conditions prevailing in their habitat for short duration? Explain with the help of one example each.

Question 15.
Mention three uses of PCR in molecular diagnostics.   

Question 16.
Explain the three ways in which natural selection operates on different traits in nature.

Question 17.
Explain the antibiotics resistance observed in bacteria in light of Darwinian selection theory.

Question 18.
What is the cause of adenosine deaminase deficiency in a person? What is the importance of this enzyme? Why is it that even after infusion of genetically engineered lymphocytes into the patient suffering from ADA deficiency, the cure is not permanent?

Question 19.
(a) What is the objective of Water Act?
(b) Mention any four problems caused due to deforestation.

Question 20.
Draw well labelled diagram of a magnified view of seminiferous tubule.    

Question 21.
(a) List two essential roles of ribosomes during translation.
(b) Who discovered nuclei acid? What was it called then?

Question 22.
Fill in the spaces a, b and c in the table showing certain events and their sites in human
(male / female) reproductive system

SECTION-D

Question 23.
In many villages, people do not go for vaccination/immunization because of some fear or religious beliefs; they feel they are healthy and they do not have the disease.

1. How can we explain to them that vaccination will help to prevent the diseases?
2. How can this idea be made to reach them?

SECTION-E

Question 24.
(a) What are

1. introns, and
2. exons?

(b) Represent schematically the steps in transcription in Eukaryotes.

OR

(a) Expand BAC and YAC.
(b) What is a promoter in a transcription unit?
(c) Differentiate between template strand and coding strand.

Question 25.
(a) What is meant by contact inhibition?
(b) Why is using tobacco in any form injurious to health? Explain.
(c) Why do sports persons often fall a victim to cocaine addiction?

OR

How are morphological and biochemical/’physiological characteristics of plants associated with resistance to certain pests? Explain with the examples

Question 26.
(a) Why pollen grains are known as living fossils?
(b) Study the population growth curves in the graph given below and answer the questions which follow:

• Identify the growth curves ‘a’ and ‘b’
• Which one of them is considered a more realistic one and why?
• If \(\cfrac { dN }{ dt } =rN\left( \cfrac { K-N }{ K } \right) \) is the equation of one of the
  growth curves, what does K stands for?
• What is symbolized by N?

OR

(a) Name any two human activities that influence carbon cycle.
(b) Describe the particular type of agriculture which is also responsible for deforestation.

Answers

SECTION-A

Answer 1.
Vector responsible for chikungunya is Aedes aegyptii.

Answer 2.
Cashew is referred to as false fruit because the thalamus also contributes to the fruit formation.

Answer 3.
Two animals that have become extinct due to over-exploitation are:

1. Dodo bird
2. Caspian Bali (species of Tiger)
3. Quagya (Any two)

Answer 4.
Phosphodiester linkage forms the backbone of a polynucleotide strand of a nucleic acid.

Answer 5.
The presence of cyanobacteria in the paddy fields is beneficial to rice crop because these bacteria have the property of nitrogen fixation due to the presence of heterocysts (nitrogen fixing cells).

SECTION-B

Answer 6.
A bisexual flower is emasculated to prevent self pollination and then bagged to further prevent its stigma from contamination by unwanted pollen. This is all done to get the desired result in the artificial hybridisation.

Answer 7.
CuT acts as an effective contraceptive for human females due to the following reasons:

1. It releases Cu ions which suppresses sperm motility.
2. Cu ions also reduces the fertilising capacity of the sperms.

Answer 8.
In PCR reaction, in the process of repeated DNA replication, the segment of DNA is amplified to approximately 1 billion time which is achieved by a thermostable DNA polymerase isolated from bacterium Thermus aquaticus.

The bacterium Thermus aquaticus (Taq) is useful in rDNA technology because it contains thermostable enzyme – DNA polymer as (Taq-DNA polymerase) which can withstand high temperature.

Answer 9.

Answer 10.
(1) Biological Products: Transgenic animals produces useful biological products only by the introduction of the portion of DNA or genes, which codes for a particular product like human protein (α-1-antitrypsin) is produced to treat emphysema.The first transgenic cow, Rosie produced human protein-enriched milk (2.4 gms per litre).

(2) Vaccine Safety: Transgenic mice are being used in testing the safety of vaccines before they are used on human beings.

(3) Chemical Safety Testing: It is also called as toxicity/safety testing. Transgenic animals are developed with genes exposed to toxic substance and are used to study their effects.

(4) Growing of Spare Parts: Spare parts (e.g., heart, pancreas) of pig for human use can be grown through the formation of transgenic animals

SECTION-C

Answer 11.

OR

1. In a transverse section, a typical microsporangium appears circular in outline.
2. It is generally surrounded by four wall layers—the epidermis, endothecium, middle layers, and the tapetum.
3. The outer three wall layers perform the function of protection and help in dehiscence of anther to release the pollen.
4. The innermost wall layer is the Tapetum. It nourishes the developing pollen grains. Cells of the tapetum possess dense cytoplasm and generally have more than one nucleus.

Answer 12.
Chromosomal theory of inheritance was proposed by Sutton and Boveri.

Answer 13.
Pathogen – Entamoeba histolytica
Organ affected – Large intestine
Symptoms:

1. Constipation
2. Abdominal pain
3. Cramps, stools are covered with mucous and blood clots.

Mode of Transmission: Houseflies act as mechanical carriers which transmit the parasite from the faces of infected person to the food and drinking water.

Answer 14.
Some organisms possess phenotypic adaptations which help them to respond quickly to an unfavourable situation.
For example, at high altitudes due to the low atmospheric pressure the human body does not get sufficient oxygen which causes altitude or mountain sickness characterised by nausea, vomiting and heart palpitation. The body compensates this low oxygen availability by increasing red blood cells, which decreases the binding-capacity of haemoglobin thereby increasing breathing rate.

Answer 15.
1. PCR (Polymerase Chain Reaction) is used to detect the presence of gene sequences of the infectious agents.
2. It is used to detect specific microbes from the samples of soil, sediments and water.
3. It is also used to detect HIV in AIDS patient.

Answer 16.
The three types of natural selection are as follows:
(1) Stabilizing Selection: The stabilizing influence of natural selection -in an environment changes little in space and time. It is also called maintenance evolution.

(2) Directional or Progressive Selection: Directional selection produces a regular change within a population in one direction in respect to certain characteristics.

(3) Disruptive Selection: In this original population splits into two groups which later evolved into two different species.

Answer 17.
In the original population of bacteria, there were some bacteria which possessed antibiotic resistant genes. When antibiotic was not used, these bacteria had no advantage with the use of antibiotics, these bacteria survived, reproduced and spread throughout the population.

Answer 18.
1. ADA is caused by the deletion of the gene responsible for the enzyme adenosine deaminase.
2. The enzyme adenosine deaminase plays crucial role in the functioning of the immune system.
3. The infusion of genetically engineered lymphocytes into the patient suffering from ADA deficiency is not a permanent cure because these cells are not immortal.

Answer 19.
(a) India has passed the Water Act in 1974. The objective of Water Act is the prevention and control of water pollution.
(b) Four problems caused due to deforestation are:       

1. Deforestation has enhanced CO₂ level which has contributed to the greenhouse effect or global warming.
2. It has caused soil erosion.
3. It has disturbed the hydrological cycle or water cycle.
4. It has lead to the loss of diversity.

Answer 20.

Answer 21.
(a) Two essential roles of ribosomes during translation are:

1. The larger subunit of ribosome has a groove for pushing out the newly formed polypeptide and protects the same from cellular enzymes.
2. The smaller unit of ribosome has a point for recognising mRNA and binding area for initiation factors.

(b) Nucleic acids were first identified by Friedrich Meischer. It was named as nucleic acids because it was isolated from the nuclei of cells.

Answer 22.
a → Ovary
b → Testis
c → Ampullary Isthmic Junction(fallopian tube)

Answer 23.
1. We can explain the villagers that vaccination is not given to cure any disease at the given time. Now they may be healthy, but when an epidemic of a disease occurs, or when they happen to encounter an infectious disease, the body does not have enough of antibodies to fight against. By vaccination, the body produces antibodies and also memory cells that can produce antibodies during an encounter with the same pathogen.

2. Advertisement propaganda can be made:

• By giving examples of cases where death has occurred due to failure of vaccination.
• Advertisement in newspapers about vaccination and its benefits.

SECTION-E

Answer 24.
(a) Coding segments in DNA are known as Exons whereas non-coding segments are known as introns.

(a) BAC → Bacterial Artificial Chromosome
YAC → Yeast Artificial Chromosome
(b) Promoter initiates the process of transcription.
(c)

Answer 25.
(a) Contact inhibition is a property by virtue of which normal cells by contact with other cells inhibit their uncontrolled growth.
(b) Harmful effects of Tobacco:

1. Tobacco contains nicotine which stimulates the adrenal gland to release adrenaline and noradrenaline into blood circulation, both of which raise blood pressure and increase , heart rate.
2. It is associated with increased incidence of cancers of lung, throat, urinary bladder, bronchitis, emphysema, gastric ulcer and coronary heart disease.
3. Tobacco chewing is associated with increase risk of cancer of the orai cavity.

(c) Sports person often take cocaine to increase their energy level for the game because it has a potent stimulating action to provide them instant energy. With regular intake they fall victim to cocaine addiction as it acts on their nervous system producing a sense of euphoria and interferes with the transport of the nano-transmitter dopamine.

OR

Morphological and biochemical characteristics of plants associated with resistance to certain pests has been seen in many host crop plants such as:

• Hairy leaves in cotton are resistant to Jassids and cereals leaf beetle in wheat.
• In wheat solid stems lead to non-preference by the stem sawfly.
• In cotton, smooth leaved and nectar-less varieties do not attract bollworms.
• In maize, high aspartic acid, low nitrogen and sugar content leads to resistance to maize stem borers.
• Thoms in Acacia, Cactus are the most common morphological means of defence in plants

Answer 26.
(a) The outer hard layer of pollen grain called the exine is made up of sporopollenin. It can withstand the worst condition of fossilization such as high temperatures and action of strong acids and alkali.

No enzyme is so far known that can degrade sporopollenin. Pollen grains are well preserved as fossils because of the presence of sporopollenin.

(b)
1. a → exponential curve
2. b→ logistic curve
3. Since resources for growth for most animal populations are finite and will become limiting sooner or later, therefore the logistic growth model/curve is considered to be a more realistic one.
4. K — carrying capacity
5. N — Population density at time “t”

OR

(a)
1. Combustion of fossil fuels
2. Deforestation

(b) Slash and Burn cultivation or Jhum cultivation or Jhuming is a type of agriculture which is responsible for deforesation. It is technically known as shifting cultivation. In India about five lakh hectares of land is cleared every year through hopping, burning the remainder, mixing the ash with soil & sowing the cleared land with crop seeds.

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CBSE Sample Papers for Class 12 Chemistry Paper 1 are part of CBSE Sample Papers for Class 12 Chemistry. Here we have given CBSE Sample Papers for Class 12 Chemistry Paper 1.

CBSE Sample Papers for Class 12 Chemistry Paper 1

Students who are going to appear for CBSE Class 12 Examinations are advised to practice the CBSE sample papers given here which is designed as per the latest Syllabus and marking scheme as prescribed by the CBSE is given here. Paper 1 of Solved CBSE Sample Paper for Class 12 Chemistry is given below with free PDF download solutions.

Time Allowed : 3 Hours
Max. Marks : 70

General Instructions

• All questions are compulsory.
• Question number 1 to 5 are very short answer questions and carry 1 mark each.
• Question number 6 to 10 are short answer questions and carry 2 marks each.
• Question number 11 to 22 are also short answer questions and carry 3 marks each.
• Question number 23 is a value based question and carry 4 marks.
• Question number 24 to 26 are long answer questions and carry 5 marks each.
• Use log table, if necessary. Use of calculators is not allowed.

Questions 

Question 1.
Why are aquatic species more comfortable in cold water as compared to warm water?

Question 2.
Write IUPAC name of

Question 3.
Which of the following complex is more stable, write its IUPAC name:
[CO(NH₃)₆]³⁺ or [Co(CO)₆]³⁺

Question 4.
Name the method used for the refining of Zirconium metal.

Question 5.
How are deltas formed?

Question 6.
Write two differences between Covalent and Molecular solids.

Question 7.
Calculate ΔG° for the following cell at 298 K.

Question 8.
An element with density 5.6 g cm 3 exists in bcc lattice with edge length 400 pm. Calculate atomic mass of this element.

Question 9.
Draw the structure of following molecules :
(a) IF^–₄
(b) XeF₆

Question 10.
Calculate mass of glucose (molar mass 180 g/mol) to be diluted in 60 g of H₂O to lower the freezing point of its solution by 0.93 K (K_f for H₂O is 1.86 K kg mol^-1)

Question 11.
(a) Which solution is used for the leaching of gold metal in the presence of air in the metallurgy of gold?
(b) Out of C and CO, which is better reducing agent at lower temperature for extraction of iron from its oxide ore.
(c) Write the principle involved in zone refining.

Question 12.
Complete the following reactions:

1. XeF₂ + PF5 →
2. H₃PO₃ \(\underrightarrow { Heat } \)
3. ClO^–₃ + Cl \(\underrightarrow { { H }^{ + } } \)

Question 13.
(a) Chlorobenzene is less soluble in water as compared to chloroethane. Explain.
(b) Which will show faster S_N1 reaction and why?

(c) Which of the following will be optically active: 2-chlorobutane or 1-chlorobutane?

Question 14.
Explain the mechanism of the following reactions :
(a) C₂H₅OH \(\xrightarrow [ { Conc.H }_{ 2 }{ SO }_{ 4 } ]{ { 170 }^{ 0 }C } \) CH₂ = CH₂
(b) CH₃ – OH \(\xrightarrow [ { H }^{ + } ]{ 413K } \) CH₃ – O – CH₃

Question 15.
(a) Distinguish between lyophilic and lyophobic colloids.
(b) Name the absorbent used for controlling of humidity in operation theatres.

Question 16.
(a) Define the limiting molar conductivity.
(b) State Kohlrausch’s law.
(a) Define corrosion.

Question 17.

1. State Henry’s law.
2. Define azeotropes. What type of azeotropes is formed by positive deviation from Raoult’s law? Give an example.

Question 18.
How would you account for the following?

1. Transition metal exhibits variable oxidation state.
2. Zr(Z = 40) and Hf(Z = 72) have almost identical radii.
3. Transition metals and their compounds act as complexing agents.

OR
Complete the following chemical equations:

1. Cr₂O^2-₇ + Fe²⁺ + H⁺ →
2. CrO^2-₄ + H⁺ →
3. MnO^–₄ + I^– + H₂O →

Question 19.

1. What type of isomerism is exhibited by the complex [Pt(NH₃)₆] [NiCl₆]?
2. Write the formula for potassium hexacyanoferrate (II).
3. Write electronic arrangement of [Co(NH₃)₆]³⁺ and discuss its geometry and magnetic behaviour.

Question 20.
Give reason for the following:

1. (CH₃)₃ P = O exists but (CH₃)₃ N = O does not.
2. Phosphorus has more negative electron gain enthalpy than nitrogen.
3. H₂Se is more acidic than H₂O.

Question 21.
Give the structure of A, B and C in the following reactions:

Question 22.
Write the name and structure of the monomers of the following polymers
(a) Buna-N
(b) Nylon-2, 6
(c) PVC

Question 23.
Read the following passage and answer the questions that follows:
Shivani has recently started facing difficulty in visualising in dark. Prema, her best friend wonders why Shivani cannot see properly in the dark, on observation she found that Shivani often carries junk foods in her lunch. Prema has started sharing her lunch full of green vegetables like carrots, tomatoes, coloured fruits, milk and other dairy products. Shivani is now better and has also started taking a balanced diet.

1. Name the disease Shivani is suffering from.
2. Name the Vitamin and its source to cure this disease.
3. What values are shown by Prema?

Question 24.
Account for the following:
(a) pK_b of aniline is more than that of methylamine.
(b) Methylamine in water reacts with FeCl₃ from hydrated ferric oxide.
(c) Why do primary amines have higher boiling point than tertiary amines?
(d) Complete the following equations:
(i) C₆H₅N₂Cl + C₂H₅OH →
(ii) C₆H₅NH₂ + (CH₃CO)₂O →
OR
(a) Give one chemical test to distinguish between:
(i) Methylamine and dimethylamine
(ii) Aniline and Benzyl amine

(b) How will you convert:
(i) Ethanoic acid to Methanamine
(ii) Aniline to p-bromoaniline
(c) Arrange according to increasing basic strength C₆H₅NH₂, C₆H₅N(CH₃)₂, (C₂H₅)₂NH, CH₃NH₂

Question 25.
(a) The rate constant for a first order reaction is 60 s-1. How much time will it take to reduce the initial concentration of the reactant to its l/16th value?
(b) Differentiate between order and molecularity of reaction.
(c) Write unit of rate constant (K) for
(i) First order reaction
(ii) 2nd order reaction
OR

1. The rate of a reaction quadruples when the temperature changes from 290 K to 310 K, calculate the activation energy for this reaction.
2. A reaction is first order wrt. P and wrt. 2nd order wrt. Q, write the differential rate equation for it.
3. Write factors (any two) that affects the rate of a chemical reaction.
4. Define specific rate constant.

Question 26.

1. Phenol is more acidic than cyclohexanol. How?
2. Which is steam volatile, 2-nitrophenol or 4-nitrophenol and why?
3. Explain following name reactions with a suitable chemical reaction.
   1. Sandmeyer’s reaction
   2. Cannizaro’s reaction

OR
(a) Write the reaction of glucose with HI.
(b) Name the force responsible for stabilisation of secondary structure of protein.
(c) Arrange according to the given instructions in increasing order:
(i) Phenol, Methoxyphenol, 2,4-Dinitrophenol (acidic strength)

Answers

Answer 1.
In cold water the concentration of dissolved oxygen gas is more and hence respiration for aquatic species will be easier so it will be comfortable as compared to warm water.

Answer 2.
2-methyl pent-4-enal

Answer 3.
[Co(CO)₆]³⁺ complex is more stable. It is due to synergic bonding between metal and carbonyl group.
IUPAC name → Hexacarbonyl cobalt (III) ion.

Answer 4.
van Arkel method

Answer 5.
Coagulation of silt present in river water due to electrolytes present in sea water leads to formation of delta.

Answer 6.

Answer 7.

= 0.34 – (- 2.37) = 2.71 V
Here change in number of electrons (n) = 2
ΔG° = – nFE_cell° = – 2 × 96500 × 2.71 = – 523.03 kJ/mole

Answer 8.
Since d = \(\frac { ZM }{ { a }^{ 3 }{ N }_{ A } } \)
From question → bcc arrangement i.e. Z = 2
a = 400 pm = 400 × 10^-10 cm = 4 × 10^-8 cm
d = 5.6 g/cm³

Answer 9.

Answer 10.

i.e. 54 g glucose needs to be added.

Answer 11.

1. Aqueous solution of NaCN or KCN is used for leaching.
2. CO at lower temperature is a better reducing agent than C for the extraction of iron from its oxide ore.
3. Impurities are more soluble in molten metal as compared to its solid state.

Answer 12.

1. XeF₂ + PF₅ → [XeF]⁺ [PF₆]^–
2. H₃PO₃ \(\underrightarrow { Heat } \) PH₃ + H₃PO₄
3. ClO^–₃ + Cl^– \(\underrightarrow { { H }^{ + } } \) Cl₂ + H₂O

Answer 13.
(a) Phenyl group is more hydrophobic as compared to smaller ethyl group, hence chloroethane is more soluble than chlorobenzene.

Due to more stable carbocation formation which is there because of more number of resonance structures.
(c) 2-chlorobutane.

Answer 14.
(a) H₂SO₄ + H₂O → H₃O⁺ + HSO^–₄

Answer 15.
(a)

(b) Silica gel

Answer 16.

1. Limiting molar conductivity : The value of molar conductivity when the concentration of electrolytes approaches zero is known as limiting molar conductivity or molar conductivity at infinite dilution. It is the maximum possible molar conductivity for any electrolyte. Represented by Δ°_m.
2. Kohlrausch’s law : It states that the limiting molar conductivity of on electrolyte is the sum of the individual contribution of the anion and cation of the electrolyte, e.g.
   Δ°_m(CH₃COOH) = λ°_CH3COO^– + λ^°_H+
3. Corrosion : The tarnishing of upper layer of any active metal due to environmental factors such as water vapours, CO₂, O₂, etc. in known as corrosion.
   For example-rusting of iron, blackening of silver, deposition of greenish layer on copper etc.

Answer 17.

(a) Henry’s law : It states that the partial pressure (p) of a gas in vapour phase is proportional to the mol fraction of the gas (x) in the solution. It is expressed as
p = k_Hx
where kH is known as Henry’s law constant and x is mol fraction.

(b) Azeotropes : It is a binary mixture, having same composition in liquid state as well as in vapour phase and boils at constant temperature like a pure liquid. If there is positive deviation, then minimum boiling azeotrope will form. In case of negative deviations, maximum boiling azeotrope will form.
Examples 95.5% Ethanol and 4.5% H₂O by volume.

Answer 18.

1. Transition metals exhibits variable oxidation state due to comparable energies of (n – 1)d and ns orbitals, so electrons from both can form bond.
2. Due to lanthanoid contraction.
3. Transition metals acts as complexing agent due to vacant d-orbitals and high charge density on metal ion.

OR

1. Cr₂O^2-₇ + 6Fe²⁺ + 14H⁺ → 2Cr³⁺ + 6Fe³⁺ + 7H₂O
2. CrO^2-₄ + H⁺ → Cr₂O^2-₇
3. 2MnO^–₄ + 10 I^– + 8H₂O → 2Mn²⁺ + 5I₂ + 16 OH^–

Answer 19.

1. Co-ordination isomerism is exhibited by the complex [Pt(NH₃)₆] [NiCl₆]
2. K₄[Fe(CN)₆]
3. Electronic arrangement for [Co(NH₃)₆]³⁺ according to VBT.
   Co → 3d⁷4s²
   Co³⁺ → 3d⁶4s⁰
   

Answer 20.

1. Due to lack of d-orbital in N, dπ-pπ bonding in not possible, hence formation of (CH₃)₃ N = O is not possible.
2. Due to small size and high electron density in valence shell of N, its electron gain enthalpy is less than phosphorous.
3. Due to longer H-Se bond than H-O bond H₂Se is more acidic.

Answer 21.

Answer 22.

Answer 23.

1. Night blindness
2. Vitamin-A, Source – Carrot, cod liver oil, butter, milk etc.
3. Care for friend, knowledge of science, sincerity in her effort.

Answer 24.
(a) Aniline is a weaker base than methylamine due to positive charge on nitrogen, which is there because of resonance. Hence its pK_b value is more than methylamine.
(b) Methyl amine gives OH- ions in water, hence FeCl₃ get hydrolysed to give hydrated ferric oxide.

(c) There is intermolecular hydrogen bonding in primary amines, which is not possible in tertiary amines. Hence primary amines have higher boiling point.

OR
(a) (i) 

(ii)

(b) (i) Ethanoic acid to methanamine

(ii) Aniline to p-bromo aniline

(c) C₆H₅NH₂ < C₆H₅N(CH₃)₂ < CH₃NH₂ < (C₂H₅)₂NH

Answer 25.

(b) Difference between order and molecularity:

(c) (i) Second^-1
(ii) mol^-1 L s^-1
OR

1. from Arrhenius equation
   
2. rate = K[P]¹ [Q]²
3. Concentration, pressure, temperature, catalyst
4. It is the rate of reaction when concentration of all the reactants is unity.

Answer 26.

1. Since phenoxide ion is resonance stablised, hence phenol is more acidic than cyclohexanol.
2. 2-nitrophenol is steam volatile due to intramolecular hydrogen bonding whereas 4-nitrophenol undergoes intermolecular hydrogen bonding and thus connected to each other to become less volatile.
3. 1. Sandmeyer’s reaction
      
   2. Cannizaro’s reaction
      HCHO \(\underrightarrow { NaOH(Conc.) } \) CH₃OH + HCOONa

OR

(b) Intermolecular and intramolecular hydrogen bonding, coloumbic interactions, disulphide
linkage etc.
(c) (i) Methoxy phenol < phenol < 2,4-dinitrophenol

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