NCERT Solutions for Class 12 Chemistry Chapter 16

Chemistry in Everyday Life – Exercise Questions with Answers

Question 16.1: Why do we need to classify drugs in different ways?

Answer:
Drugs are classified in different ways to better understand their chemical structure, therapeutic effects, and mode of action. This classification helps in organizing drugs systematically, identifying their uses based on pharmacological action, understanding their chemical nature, prescribing them effectively, and avoiding harmful drug interactions.

Question 16.2: Explain the term ‘analgesic’. Give two examples.

Answer:
Analgesics are drugs that relieve pain without causing unconsciousness or affecting the nervous system. They are classified as:
– Non-narcotic analgesics: e.g., Aspirin, Paracetamol
– Narcotic analgesics: e.g., Morphine, Codeine

Question 16.3: Write the chemical equation showing the conversion of salicylic acid to aspirin.

Answer:
C₇H₆O₃ (salicylic acid) + (CH₃CO)₂O → C₉H₈O₄ (aspirin) + CH₃COOH
Salicylic acid reacts with acetic anhydride in the presence of an acid catalyst to form aspirin and acetic acid.

Question 16.4: What are antiseptics? Give an example.

Answer:
Antiseptics are chemicals that prevent the growth of microorganisms and are safe to use on living tissues. They are used on wounds, cuts, and skin infections.
Example: Dettol (a mixture of chloroxylenol and terpineol)

Question 16.5: Why are synthetic detergents preferred over soap?

Answer:
Synthetic detergents are preferred over soaps because:
– They can be used in hard water.
– They have better cleaning efficiency.
– They work in both acidic and basic conditions.
– They do not form insoluble salts in water.

Question 16.6: Explain the following terms with suitable examples:

Answer:
(i) Cationic detergents: Quaternary ammonium salts with a positively charged ion. Example: Cetyltrimethylammonium bromide (used in hair conditioners).
(ii) Anionic detergents: Detergents with negatively charged ions, effective for dirt removal. Example: Sodium lauryl sulphate (used in toothpaste and shampoos).
(iii) Non-ionic detergents: Detergents without any charge, formed by reaction of polyethylene glycol with stearic acid. Example: Polyethylene glycol stearate (used in cosmetics).

Question 16.7: What are food preservatives?

Answer:
Food preservatives are chemicals used to prevent spoilage of food due to microbial growth or oxidation.
Examples: Sodium benzoate, Sodium metabisulphite

Question 16.8: Explain the term artificial sweeteners. Give two examples.

Answer:
Artificial sweeteners are substances that provide sweetness without the calories of sugar. They are beneficial for diabetic patients and those controlling calorie intake.
Examples: Aspartame, Saccharin

Question 16.9: Name a sweetening agent used in soft drinks.

Answer:
Aspartame is commonly used in soft drinks as a sweetening agent.

Question 16.10: What are antibiotics? What precautions must be taken while taking antibiotics?

Answer:
Antibiotics are chemical substances produced by microorganisms that inhibit the growth of or destroy harmful microbes.
Precautions to be taken:
– Complete the full course as prescribed.
– Do not self-medicate.
– Avoid using antibiotics for viral infections like cold and flu.
– Use antibiotics only on medical prescription to prevent antibiotic resistance.