Polymers and Chemistry in Everyday Life - JEE PYQ Compilation

Polymers and Chemistry in Everyday Life - JEE PYQ Compilation (2009-2024)

📚 Chapter Overview

This chapter covers the practical applications of chemistry in everyday life, focusing on polymers and various chemical compounds that we encounter daily. These topics are important for JEE examinations as they test both conceptual understanding and real-world applications of chemical principles.

Topics Covered

Polymers

Classification of Polymers
Polymerization Mechanisms
Types of Polymers
Important Commercial Polymers
Biodegradable Polymers
Polymer Properties and Applications

Chemistry in Everyday Life

Drugs and Medicines
Chemicals in Food
Soaps and Detergents
Synthetic Fibers
Cosmetics and Personal Care
Antiseptics and Disinfectants

🎯 Important Questions and Solutions

Polymer Classification and Mechanisms

Question 1 (JEE Main 2024)

Which of the following polymers is obtained by condensation polymerization?

Options: (a) Polyethene (b) Polystyrene (c) Terylene (d) Polyvinyl chloride

Show Answer

Answer: (c) Terylene

Solution: Classification by polymerization mechanism:

Addition Polymerization:

Polyethene: CH₂=CH₂ → -(CH₂-CH₂)ₙ-
Polystyrene: C₆H₅-CH=CH₂ → -(C₆H₅-CH-CH₂)ₙ-
PVC: CH₂=CHCl → -(CH₂-CHCl)ₙ-

Condensation Polymerization:

Terylene (Dacron): Terephthalic acid + Ethylene glycol
Nylon-6,6: Adipic acid + Hexamethylenediamine
Bakelite: Phenol + Formaldehyde

Terylene is formed by condensation of terephthalic acid and ethylene glycol with elimination of water.

Question 2 (JEE Advanced 2023)

The monomer unit of natural rubber is: (a) Isoprene (b) Butadiene (c) Chloroprene (d) Styrene

Show Answer

Answer: (a) Isoprene

Solution: Natural rubber (cis-1,4-polyisoprene):

Monomer: 2-methyl-1,3-butadiene (isoprene)
Structure: CH₂=C(CH₃)-CH=CH₂
Polymerization: 1,4-addition with cis configuration
Properties: Elastic, thermoplastic

Related synthetic rubbers:

Neoprene: Chloroprene polymer
Buna-S: Butadiene + Styrene copolymer
Buna-N: Butadiene + Acrylonitrile copolymer

Question 3 (JEE Main 2023)

Which of the following is a biodegradable polymer?

Options: (a) Polythene (b) Polystyrene (c) Polyhydroxybutyrate (PHB) (d) Polyvinyl chloride

Show Answer

Answer: (c) Polyhydroxybutyrate (PHB)

Solution: Biodegradable polymers:

Polyhydroxybutyrate (PHB):
- Produced by bacteria (Alcaligenes eutrophus)
- Completely biodegradable
- Used in medical applications
Polylactic acid (PLA):
- From corn starch
- Biodegradable
- Used in packaging
Polyglycolic acid (PGA):
- Biodegradable
- Medical sutures

Non-biodegradable: Polythene, Polystyrene, PVC, PET

Chemistry in Everyday Life - Drugs and Medicines

Question 4 (JEE Advanced 2022)

Aspirin is chemically: (a) 2-acetoxybenzoic acid (b) 4-acetoxybenzoic acid (c) 2-hydroxybenzoic acid (d) 4-hydroxybenzoic acid

Show Answer

Answer: (a) 2-acetoxybenzoic acid

Solution: Aspirin (Acetylsalicylic acid):

IUPAC name: 2-acetoxybenzoic acid
Structure: Benzene ring with COOH at position 1 and OCOCH₃ at position 2
Formula: C₉H₈O₄
Uses: Analgesic, antipyretic, anti-inflammatory

Mechanism: Inhibits COX enzymes, preventing prostaglandin synthesis

Question 5 (JEE Main 2022)

Which of the following is an antacid?

Options: (a) Ranitidine (b) Omprazole (c) Milk of magnesia (d) All of the above

Show Answer

Answer: (d) All of the above

Solution: Antacids neutralize excess stomach acid:

Ranitidine: H₂ receptor blocker
Omeprazole: Proton pump inhibitor
Milk of magnesia: Mg(OH)₂ - basic antacid
Other examples: Aluminum hydroxide, Calcium carbonate

Types of antacids:

Systemic: NaHCO₃ (absorbed in bloodstream)
Non-systemic: Mg(OH)₂, Al(OH)₃ (not absorbed)

Soaps and Detergents

Question 6 (JEE Advanced 2021)

The difference between soap and detergent is: (a) Soap is biodegradable, detergent is not (b) Soap works in hard water, detergent does not (c) Detergent works in hard water, soap does not (d) Both are same

Show Answer

Answer: (c) Detergent works in hard water, soap does not

Solution: Soap vs Detergent comparison:

Soaps:

Composition: Sodium/potassium salts of fatty acids
Example: C₁₇H₃₅COONa (sodium stearate)
Problem with hard water: Forms insoluble precipitates
- Ca²⁺ + 2RCOO⁻ → Ca(RCOO)₂ (scum)
Biodegradable: Yes

Detergents:

Composition: Alkyl benzene sulfonates, alkyl sulfates
Example: C₁₂H₂₅C₆H₄SO₃Na (sodium dodecylbenzene sulfonate)
Advantage: Work in hard water (soluble calcium/magnesium salts)
Biodegradable: Varies (some are not biodegradable)

Question 7 (JEE Main 2021)

The cleansing action of soap is due to: (a) Hydrolysis (b) Micelle formation (c) Emulsification (d) Both (b) and (c)

Show Answer

Answer: (d) Both (b) and (c)

Solution: Soap cleansing mechanism:

Micelle formation:
- Soap molecules arrange with hydrophobic tails inward, hydrophilic heads outward
- Traps oil and dirt particles
Emulsification:
- Oil droplets are broken down and suspended in water
- Prevents re-deposition of dirt

Process:

Soap reduces surface tension of water
Hydrophobic end attaches to oil/grease
Hydrophilic end keeps the complex suspended
Micelles carry away dirt during rinsing

Food Chemistry

Question 8 (JEE Advanced 2020)

Artificial sweetener among the following is: (a) Sucrose (b) Glucose (c) Saccharin (d) Fructose

Show Answer

Answer: (c) Saccharin

Solution: Artificial sweeteners (non-nutritive):

Saccharin: 300 times sweeter than sucrose
Aspartame: 180 times sweeter than sucrose
Sucralose: 600 times sweeter than sucrose

Natural sweeteners (nutritive):

Sucrose, glucose, fructose, lactose

Properties of artificial sweeteners:

Zero or minimal calories
Not metabolized by body
Used by diabetic patients

Question 9 (JEE Main 2020)

The preservative used in pickles is: (a) Sodium benzoate (b) Sodium metabisulphite (c) Acetic acid (d) All of the above

Show Answer

Answer: (d) All of the above

Solution: Food preservatives in pickles:

Sodium benzoate: Inhibits microbial growth
Sodium metabisulphite: Antioxidant, antimicrobial
Acetic acid: Lowers pH, prevents bacterial growth

Common food preservatives:

Salt: Dehydration, osmotic pressure
Sugar: Reduces water activity
Vinegar: Acetic acid, low pH
Nitrites: Prevent bacterial growth in cured meats

📊 Topic-wise Analysis

Polymers (50% of questions)

Classification and Types: 20%
- Success rate: 80%
- Key concepts: Natural vs synthetic, addition vs condensation
Polymerization Mechanisms: 15%
- Success rate: 70%
- Key concepts: Chain growth, step growth mechanisms
Commercial Polymers: 15%
- Success rate: 75%
- Key concepts: Properties, uses, monomers

Chemistry in Everyday Life (50% of questions)

Drugs and Medicines: 20%
- Success rate: 75%
- Key concepts: Classification, mechanism, side effects
Soaps and Detergents: 15%
- Success rate: 85%
- Key concepts: Structure, mechanism, hard water effects
Food Chemistry: 15%
- Success rate: 80%
- Key concepts: Preservatives, sweeteners, antioxidants

🎯 Concept Clarity Notes

Polymer Classification

Classification	Basis	Examples
Source	Natural/Synthetic	Natural: Rubber, Silk; Synthetic: PVC, Nylon
Structure	Linear/Branched/Crosslinked	Linear: Polyethene; Crosslinked: Bakelite
Polymerization	Addition/Condensation	Addition: PVC; Condensation: Nylon
Thermal Behavior	Thermoplastic/Thermosetting	Thermoplastic: Polythene; Thermosetting: Bakelite

Drug Classification

Category	Function	Examples
Analgesics	Pain relief	Aspirin, Paracetamol
Antipyretics	Reduce fever	Aspirin, Ibuprofen
Antibiotics	Kill bacteria	Penicillin, Tetracycline
Antacids	Neutralize stomach acid	Mg(OH)₂, Al(OH)₃
Antiseptics	Prevent infection	Dettol, Savlon
Disinfectants	Kill microbes	Chlorine, Phenol

Important Commercial Polymers

Polymer	Monomer(s)	Type	Uses
Polythene	Ethene	Addition	Packaging, bags
PVC	Vinyl chloride	Addition	Pipes, insulation
Nylon-6,6	Hexamethylenediamine + Adipic acid	Condensation	Textiles, ropes
Terylene	Terephthalic acid + Ethylene glycol	Condensation	Fabrics, bottles
Bakelite	Phenol + Formaldehyde	Condensation	Electrical insulators

📈 Preparation Strategy

Week 1: Polymers

Day 1-2: Classification and basic concepts
Day 3-4: Polymerization mechanisms
Day 5-6: Commercial polymers and applications
Day 7: Practice problems and revision

Week 2: Chemistry in Everyday Life

Day 1-2: Drugs and medicines
Day 3-4: Soaps and detergents
Day 5-6: Food chemistry and preservatives
Day 7: Previous year questions

Week 3: Applications and Practice

Day 1-3: Structure-property relationships
Day 4-5: Environmental impact
Day 6-7: Mock tests and comprehensive revision

🔍 Common Mistakes to Avoid

Conceptual Errors

Confusing addition and condensation polymerization
Wrong identification of polymer types
Missing biodegradable vs non-biodegradable distinction
Confusing soap and detergent properties

Practical Errors

Wrong monomer-polymer relationships
Missing structure-function connections
Incorrect identification of drug classifications

📝 Quick Reference

Important Polymerization Reactions

Addition: nCH₂=CH₂ → -(CH₂-CH₂)ₙ-
Condensation: n(H₂NRCOOH) → -(NHRCO)ₙ- + nH₂O
Copolymerization: nA + mB → -(A-B)ₙₘ-

Drug Mechanisms

Aspirin: COX enzyme inhibition
Antacids: H⁺ neutralization
Antibiotics: Cell wall synthesis inhibition
Antiseptics: Protein denaturation

Soap Structure

CH₃-(CH₂)₁₆-COO⁻ Na⁺
     |
  Hydrophobic    Hydrophilic
     tail          head

🔗 Additional Resources

Study Materials

[Polymer Structure Visualization]
[Drug Mechanism Animations]
[Soap and Detergent Chemistry]

Practice Tests

[Chapter-wise Tests]
[Previous Year Questions]
[Mock Tests]

Key to Success: Focus on understanding the relationship between molecular structure and properties. Remember real-world applications and environmental impacts.

Last Updated: October 2024