Important Questions Class 12 Chemistry Chapter 16

Important Questions Class 12 Chemistry Chapter 16

Important Questions For CBSE Class 12 Chapter 16 – Chemistry In Everyday Life

Chemistry is an important branch of science. The water that we drink, the food that we consume, the clothes that we wear are all chemical compounds. Still, some compounds are there which are extremely crucial and have economic benefits also. Hence, they are produced in huge quantities in industries. For, example, soaps, detergents, medicines, artificial sweeteners, etc. It is surprising to think that the detergent we use to clean our clothes is prepared from the same sodium that is used to prepare edible salt. Again, drugs, which are generally considered harmful to the nervous system, are used to cure mental illness. So, our daily lives highly depend on chemical compounds. Important Questions Class 12 Chemistry Chapter 16 will help students revise the chapter quickly through questions-answers. This question set follows CBSE Syllabus. So, students need  not  worry about which questions they should practise and which ones  they can skip. These questions are selected by subject matter experts after consulting the question papers of the past years. Students can rely on them and practise more questions to get  excellent marks in the exam.

Very Short Answer  Questions (1 Mark)

1. Write down the name of the semi-synthetic form of penicillin used to treat bacterial infection.

Ans: Ampicillin is the semi-synthetic modification of penicillin that is used to treat bacterial infections.

2. What is an antibiotic? How do they work?

Ans: An antibiotic is a drug produced by the fermentation process to fight against bacterial diseases. Antibiotics destroy the cell walls of the bacteria and disrupt their metabolic activities causing their death. For this reason, antibiotics are used as medicines for humans as well as animals.

3. What do you mean by tranquiliser?

Ans. A tranquilser is a chemical substance used mainly to reduce stress, anxiety and treat other mental illnesses. The patient feels euphoria after taking it and thus feels free from the worry and tension that otherwise troubles them.. chlordiazepoxide, meprobamate, veronal, amytal, nembutal, luminal, and phenelzine, etc. are some of the well-known tranquillisers.

4. What are analgesics?

Ans. Analgesics are drugs that relieve pain without harming the nervous system or producing any kind of disorientation. Aspirin, morphine, heroin, and codeine are examples of analgesics.

5. A chemical substance made up of different ammonium salts is used as a detergent in our daily lives. It also contains Br as an important element. Identify the substance.

Ans: The detergent made up of a mixture of different ammonium salts that also contains Br as an important element is- iscetyltrimethylammonium bromide, also called Cetrimide.

6. Write down the use of bithional in industrial chemistry.

Ans: Bithional is an antibacterial disinfectant. Bithional is used in soap to act as an antibacterial agent that also decreases odours caused by microbial breakdown of organic compounds on the skin.

 Short  Answer Questions (2 Marks)

Q1. The analysis of the water in a certain area shows that the water contains chloride salts of magnesium and calcium. People in that area find that it is difficult to wash clothes with soap. So, they have started using  detergent. What is the reason that ordinary washing soaps are not effective for washing clothes in that area?

Ans: The hardness of water is determined by the presence of chloride salts of magnesium and calcium. As the amount of these salts increases in the water the hardness of the water also increases. Detergents can clean clothes better as they are made up of various petroleum compounds. They can easily displace the calcium and magnesium ions in water. So, the hardness of the water has little effect on them. Therefore, synthetic detergents are more useful for washing clothes with hard water than with soft water.

Q2. Pick  the odd one out from the following.

Erythromycin, penicillin, tetracycline, chloramphenicol

Ans: The chemical substances mentioned here are antibiotics but among them only penicillin is available on the market in tablet form.

Q3. Antiallergics and antacids both are medicines. Then why are only antacids used to reduce the stomach acidity and not antiallergics?

Ans: Though antiallergic drugs and antacids both are used as medicines, they are used for different purposes. Antiallergics medications are used to reduce the effect of histamines in the body that causes allergy in the body. So, they are called antihistamines. Antacids, on the other hand, are used to reduce the acidity of the stomach. They are bicarbonate salt of sodium or hydroxides of magnesium and aluminium. They do not contain any antiallergenic elements. Hence, these two medicines cannot be used interchangeably.

Q4. Morphine, heroin, aspirin, codeine all come under the category of drugs. Which one is different among them? Why is it different from the other drugs?

Ans: Morphine, heroin, aspirin, codeine all come under the category of drugs. All of them are analgesics, but aspirin differs from the others because of its anti-inflammatory property.

Q5. Write down the IUPAC name of bithionol. What is its significance in the medical industry?

Ans. The IUPAC name of bithionol is 2, 4-dichloro- 6-(3, 5-dichloro-2-hydroxyphenyl) sulfonyl phenol. This is an antiseptic used to treat minor cuts and wounds.

Q6. Birth control pills essentially contain a mixture of synthetic estrogen and progesterone. What are estrogen and progesterone? Why are they used in birth control pills?

Ans: Estrogen and progesterone are female hormones that are crucial for pregnancy as these two hormones regulate the ovulation process and menstrual cycle in women.

A mixture of these hormones is used in birth control pills to prevent pregnancy in the following way:

• Birth control pills restrict the development of the ovum and make it unable to absorb sperm, thus preventing conception.
• Some contraceptive pills act by thickening the cervical mucus near the uterus’ entrance, so that sperm cannot reach the egg.
• Furthermore, these tablets can alter the uterine linings and prevent the fertilised egg from developing in the uterus.

Q7. Why are soaps used as cleaning agents?

Ans: The diets that stain our clothes are basically oil particles which do not get dissolved in water. Aqueous solution of soap produces hydrophilic and hydrophobic ions. The hydrophilic ions remain in the water while the hydrophobic ions remain with the oil particles. Thus, the ions separate the oil or dirt from clothes and break them in a manner that they get dissolved in the water. When the clothes are removed from the water the clothes are clean.

Q8. Why are detergents containing unbranched chains preferred to those that contain branched chains?

Ans. This issue is related to the safety of the environment. Detergents containing branched chain hydrocarbons are considered non-biodegradable as they cannot be broken down by bacteria present in the soil. Hence, detergents with straight hydrocarbon chains are preferred over those containing branched chains.

Q9. Low levels of noradrenaline may lead to depression, hypotension, and attention deficit hyperactivity disorder. How can this condition be cured?

Ans: Depression, hypotension, attention deficit hyperactivity disorder (ADHD), etc. are caused by a lack of noradrenaline. Antidepressant medications delay the noradrenaline metabolism by inhibiting the enzymes that break down the noradrenaline hormone. Thus, antidepressants give the neurotransmitters time enough to activate their receptors for a longer period of time. Iproniazid and phenelzine are two examples of such medications.

 Questions and Answers (3 Marks)

Q1. Sodium hydrogen carbonate and ranitidine are used as antacids. Which one would you prefer? State your reason(s).

Ans: Antacids reduce acidity in two ways. Firstly, they can neutralise the excess hydrochloric acid produced in the stomach. Secondly, they can regulate the secretion of acid at its source. Sodium hydrogen carbonate, magnesium hydroxide, aluminium hydroxide, etc. work by neutralising the acid’s effect. However, the root cause remains unaddressed in this way. On the other hand, antacids like cimetidine and ranitidine act by regulating the acidity at the source. They inhibit the interaction between histamine and the receptors on the stomach walls. In this way, the quantity of acid in the stomach gets reduced. So, ranitidine is considered a better antacid than sodium hydrogen.

Q2. Identify the following substances:

(i). It is a white, crystalline powder, 550 times sweeter than cane sugar, and found in urine in its unaltered form.

Ans: This substance is ortho-sulfabenzamide or better known as saccharin. It was discovered in 1879. It is mainly used in food as a sweetening agent.

(ii). It is 200 times as sweet as regular sugar, and its use is limited to cold food and soft drinks as it is unstable at cooking temperature.

Ans: This substance is aspartame. It is an artificial sweetener commonly used in beverages. When it is heated to a high temperature the peptide bond breaks down and produces amino acid. It also loses its sweetening property at a high temperature which is why it cannot be used in baked food.

(iii). It is a trichloro derivative of Sucrose and it is stable at room temperature; it tastes like sugar but unlike sugar it has zero calorific value.

Ans: Sucralose is a trichloro derivative of sucrose. It is an artificial sweetener that tastes and looks like sugar. It is stable at room temperature but at high temperature it decomposes into carbon dioxide, hydrogen chloride, and other minor byproducts of chlorine.

Q.3. What are enzyme inhibitors? Differentiate between competitive inhibitors and non-competitive inhibitors.

Ans. Enzymes help in chemical reactions by holding the substrate molecules and providing functional groups on those same molecules to carry the reaction. The substrates are usually attracted by the active side of the enzymes. Some drugs, however, influence the enzymes’ behaviour by inhibiting their activities. These drugs are called enzyme inhibitors.

Based on the attachment of a neutral substrate to the active site of enzymes, these drugs can be divided into two categories: competitive and non-competitive inhibitors.

• Competitive inhibitors compete with the substrate molecules to get attached with the active site of the enzymes; whereas some inhibitors prefer to get bound with another site of the enzyme instead of competing with substrate molecules. They are called non-competitive inhibitors.

• Competitive inhibitors do not influence the activities of the enzymes; but non-competitive inhibitors alter the activities in such a way that natural substrates cannot recognise the enzymes.

Q.4.(i) Cooked food often becomes spoiled, but pickles do not get spoiled easily. Why?

Ans. Pickles contain a lot of salt and oil which together act as preservatives. They do not let the moisture and air pass through them, thus protecting the substances in the pickle from bacteria. Cooked foods do not contain that much oil and salt. So, they are easily exposed to bacterias that contaminate  the food..

(ii) Write down two differences between bathing soaps and washing soaps.

Ans. The differences between bathing soaps and washing soaps are as follows:

• Bathing soaps are produced from potassium salts whereas washing soaps are salts of sodium.
• Bathing soaps are soft and free from unused alkali but washing soaps are hard and may contain residual alkali.