Introduction to NCERT Exemplar Solutions for Class 12 Chemistry Chapter 16: Chemistry in Everyday Life
Chemistry plays a crucial role in our daily life, influencing health, hygiene, nutrition, and the environment. Chapter 16 of Class 12 Chemistry explores the chemistry behind drugs, food additives, detergents, and chemicals used in everyday products. The NCERT Exemplar Solutions for this chapter provide step-by-step reasoning for conceptual and application-based problems, helping students understand the practical significance of Chemistry in day-to-day life.
Drugs and Medicinal Chemistry
Drugs are chemical substances used to prevent, cure, or alleviate diseases. They are classified into different types:
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Analgesics and antipyretics: Reduce pain and fever, e.g., paracetamol and aspirin.
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Antibiotics: Combat bacterial infections, e.g., penicillin and tetracycline.
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Antiseptics and disinfectants: Kill or inhibit microorganisms on external surfaces, e.g., phenol and boric acid.
Exemplar questions often require students to identify functional groups in drugs, explain their mode of action, or distinguish between different types of drugs based on chemical structure. Mechanistic reasoning is emphasized for reactions like the acetylation of salicylic acid to form aspirin.
Chemistry of Food Additives
Food additives improve shelf life, taste, and appearance of foods. Common categories include:
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Preservatives: Prevent microbial growth, e.g., sodium benzoate.
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Antioxidants: Prevent oxidation of food components, e.g., ascorbic acid.
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Coloring and flavoring agents: Enhance visual and sensory appeal.
Exemplar solutions provide detailed explanations of the chemical principles behind the action of these additives, helping students connect theoretical chemistry with practical applications. Questions often require reasoning about safety, efficacy, and permissible limits of additives.
Detergents and Soaps
Soaps and detergents are surfactants that remove dirt and grease.
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Soaps are sodium or potassium salts of long-chain fatty acids and act through micelle formation, where non-polar tails trap grease and polar heads interact with water.
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Detergents are synthetic surfactants that are effective in hard water and do not form scum. Examples include sodium dodecyl sulfate and alkylbenzene sulfonates.
Exemplar problems often ask students to compare soaps and detergents, explain micelle formation, and discuss environmental effects of synthetic detergents.
Chemicals in Cosmetics and Everyday Products
Many cosmetics, toiletries, and cleaning agents contain chemical compounds with specific functions:
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Antiperspirants contain aluminum or zirconium salts to reduce perspiration.
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Shampoos and conditioners contain surfactants and cationic compounds for cleaning and conditioning hair.
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Toothpaste contains abrasives, fluoride compounds, and surfactants for dental hygiene.
Exemplar questions link chemical structure and function, encouraging students to think critically about formulation and effectiveness.