Chapter 15: Polymers Class 12 Chemistry NCERT Solutions

Study types, properties, and uses of polymers through NCERT Solutions for Class 12 Chemistry Chapter 15. Understand polymerization reactions easily. Download free PDFs and scroll down to practice better with complete answers.

To Help You Excel: NCERT Solutions for Class 12 Chemistry Chapter 15 – Polymers

Our detailed and student-friendly NCERT Solutions for Chapter 15 – Polymers are tailored to the latest syllabus and exam patterns. These solutions help you understand polymer formation, types, and properties with simplified explanations and clear examples.

What You Will Learn in Chapter 15 – Polymers

This chapter provides an in-depth study of polymers — what they are, how they are formed, and their applications in daily life and industry.

Key Topics Covered:

Introduction to Polymers:

  • Definition of monomers and polymers

  • Types of polymerisation reactions

  • Importance of polymers in everyday materials

Classification of Polymers:

  • Based on source: Natural, Synthetic, and Semi-synthetic polymers

  • Based on structure: Linear, Branched, and Cross-linked polymers

  • Based on polymerisation mechanism: Addition and Condensation polymers

Types of Polymerisation:

  • Addition Polymerisation (Chain-Growth): e.g., formation of polyethene, polystyrene

  • Condensation Polymerisation (Step-Growth): e.g., nylon-6,6 and terylene

  • Copolymerisation: Formation of polymers from different monomers (e.g., Buna-S, Buna-N)

Important Commercial Polymers:

  • Synthetic fibers: Nylon-6, Nylon-6,6, Terylene

  • Rubbers: Natural rubber, Vulcanised rubber, Synthetic rubber (Buna-S, Neoprene)

  • Plastic materials: Polyethene, PVC, Bakelite, Melamine-formaldehyde resin

Biodegradable Polymers:

  • Introduction and need for environmentally friendly polymers

  • Examples: PHBV, Nylon-2-Nylon-6

Why Use Our NCERT Solutions for Chapter 15?

Our solutions are prepared with a focus on clarity and accuracy. All NCERT questions are explained in an easy-to-understand manner, helping students build a solid understanding of polymer chemistry and how it applies to both academics and industry.

Highlights of Our Solutions:

  • Step-by-step answers to all NCERT Intext and Exercise Questions

  • Covers mechanisms, structures, and uses of major polymers

  • Clearly labelled diagrams and structures for easy learning

  • Ideal for CBSE board preparation as well as competitive exams like JEE and NEET

  • Written in simple, concise, and student-friendly language

NCERT Solutions for Chapter 15 – Polymers (Intext + Exercise)

Intext Questions

  • Complete solutions to Intext Questions 15.1 to 15.5

  • Each question explained with the underlying concept and relevant examples

Exercise Questions

  • Fully solved Exercise Questions 15.1 to 15.14

  • Covers all aspects including naming polymers, types of polymerisation, synthetic rubbers, and biodegradable polymers

  • Easy-to-remember explanations for polymer names, monomers, and properties

Download Chapter 15 Solutions PDF – Polymers

For convenient access and offline study, download the free PDF of Class 12 Chemistry Chapter 15 – Polymers Solutions.

What’s Inside the PDF:

  • Clean and print-ready format

  • All NCERT questions with structured, easy explanations

  • Useful for quick revisions before exams

  • Perfect for CBSE and entrance exam preparation

Recommended Preparation Tips:

  • Revise definitions and types of polymerisation thoroughly

  • Memorize important monomers and polymers along with their structures

  • Focus on commercial and synthetic applications of polymers

  • Understand differences between addition and condensation polymerisation

  • Practice reaction mechanisms and naming of polymers

Additional Study Resources:

  • Class 12 Chemistry Notes – Chapter 15 Polymers

  • NCERT Exemplar Solutions for Chapter 15

  • Previous Year Questions from CBSE, NEET, and JEE based on Polymers

  • Polymerisation Mechanism Charts and Quick Revision Tables

By mastering the content in this chapter and using our guided solutions, you’ll gain a deeper understanding of how polymers are central to both modern materials and industrial chemistry, ensuring strong performance in your board exams and competitive entrance tests.

Section Name Topic Name
15
Polymers
15.1
Classification of Polymers
15.2
Types of Polymerisation Reactions
15.3
Molecular Mass of Polymers
15.4
Biodegradable Polymers
15.5
Polymers of Commercial Importance

NCERT Solutions for Class 12 Chemistry Chapter 15

Polymers – Intext and Exercise Questions with Answers

Question 15.1: What are polymers?

Answer:
Polymers are large molecules composed of repeating structural units called monomers, connected by covalent bonds. They generally possess high molecular masses ranging from 10³ to 10⁷ u. Examples include polythene, nylon-6,6, bakelite, and natural rubber.

Question 15.2: How are polymers classified on the basis of structure?

Answer:
Polymers are classified as:
– Linear polymers: Long, straight chains. (e.g., HDPE, PVC)
– Branched-chain polymers: Chains with side branches. (e.g., LDPE, starch)
– Cross-linked (network) polymers: Three-dimensional structures. (e.g., bakelite, melamine)

Question 15.3: Write the names of the monomers of the following polymers:

Answer:
(i) Nylon-6,6: Hexamethylene diamine and adipic acid
(ii) Nylon-6: Caprolactam
(iii) Teflon: Tetrafluoroethene (CF₂=CF₂)

Question 15.4: Classify the following as addition or condensation polymers: Terylene, Bakelite, PVC, Polythene.

Answer:
– Addition polymers: PVC, Polythene
– Condensation polymers: Terylene, Bakelite

Question 15.5: Explain the difference between Buna-N and Buna-S.

Answer:
– Buna-S: Copolymer of butadiene and styrene. Used in tyres, footwear.
– Buna-N: Copolymer of butadiene and acrylonitrile. Oil-resistant, used in fuel hoses and gaskets.

Question 15.6: Arrange the following polymers in increasing order of intermolecular forces:

Answer:
(i) Buna-S < Polythene < Nylon-6,6
(ii) Neoprene < PVC < Nylon-6

Question 15.1 (Exercise): Explain the terms polymer and monomer.

Answer:
A polymer is a high molecular mass substance formed by repeated linkage of monomers. A monomer is a simple molecule that combines to form a polymer. Example: Ethene forms polythene.

Question 15.2: What are natural and synthetic polymers? Give two examples of each.

Answer:
– Natural polymers: Found in nature. (e.g., Proteins, cellulose)
– Synthetic polymers: Man-made polymers. (e.g., Nylon-6,6, Bakelite)

Question 15.3: Distinguish between homopolymer and copolymer.

Answer:
– Homopolymer: Formed from one type of monomer (e.g., Polyethene).
– Copolymer: Formed from two or more different monomers (e.g., Buna-S).

Question 15.4: How do you explain the functionality of a monomer?

Answer:
Functionality refers to the number of bonding sites on a monomer. Monomers with functionality 2 form linear polymers, while those with functionality 3 or more form network polymers.

Question 15.5: Define the term polymerisation.

Answer:
Polymerisation is the process of linking monomers through covalent bonds to form large chain-like molecules called polymers.

Question 15.6: Is (-CH₂-CH=CH₂-)n a homopolymer or copolymer?

Answer:
It is a homopolymer formed from the monomer propylene (CH₂=CH–CH₃).

Question 15.7: In which classes are the polymers classified based on molecular forces?

Answer:
Polymers are classified as:
– Elastomers (e.g., rubber)
– Fibres (e.g., nylon)
– Thermoplastics (e.g., polythene)
– Thermosetting polymers (e.g., bakelite)

Question 15.8: How can you differentiate between addition and condensation polymerisation?

Answer:
– Addition polymerisation: No elimination of small molecules. (e.g., Polythene)
– Condensation polymerisation: Elimination of small molecules like H₂O or HCl. (e.g., Nylon-6,6)

Question 15.9: Explain the term copolymerisation and give two examples.

Answer:
Copolymerisation involves different monomers combining to form a polymer.
Examples: Buna-S, Buna-N

Question 15.10: Write the free radical mechanism for polymerisation of ethene.

Answer:
Initiation: R–O–O–R → 2R•
Chain initiation: R• + CH₂=CH₂ → R–CH₂–CH₂•
Chain propagation: R–CH₂–CH₂• + CH₂=CH₂ → R–(CH₂–CH₂)₂•
Chain termination: Combination of two radical chains.

Question 15.11: Define thermoplastics and thermosetting polymers with two examples each.

Answer:
– Thermoplastics: Soften on heating. (e.g., PVC, polythene)
– Thermosetting polymers: Harden permanently on heating. (e.g., Bakelite, melamine)

Question 15.12: Write the monomers used for the preparation of Buna-S and Buna-N.

Answer:
– Buna-S: Butadiene and styrene.
– Buna-N: Butadiene and acrylonitrile.

Question 15.13: Write the name and structure of one common initiator used in free radical addition polymerisation.

Answer:
Benzoyl peroxide (C₆H₅CO–O–O–COC₆H₅) is a common initiator.

Question 15.14: How does the presence of double bonds in rubber molecules influence their structure and reactivity?

Answer:
Double bonds provide elasticity and flexibility to rubber. They also allow reactions like vulcanisation, enhancing strength and resistance.

Question 15.15: Discuss the main purpose of vulcanisation of rubber.

Answer:
Vulcanisation improves the elasticity, strength, and durability of rubber by forming cross-links between polymer chains.

Question 15.16: What are the monomeric repeating units of Nylon-6 and Nylon-6,6?

Answer:
– Nylon-6: Caprolactam
– Nylon-6,6: Hexamethylene diamine and adipic acid

Question 15.17: Write the names and structures of monomers of the following polymers:

Answer:
(i) Buna-N: Butadiene and acrylonitrile
(ii) Teflon: Tetrafluoroethene
(iii) PVC: Vinyl chloride
(iv) Bakelite: Phenol and formaldehyde

Question 15.18: Identify the monomer in the following polymeric structures:

Answer:
(i) Hexamethylene diamine and adipic acid (for Nylon-6,6)
(ii) Maleic anhydride and ethylene glycol (for a polyester)