NCERT Solutions Class 12 Chemistry Chapter 15
NCERT Solutions Class 12 Chemistry Chapter 15 Polymers
CBSE Class 12 Chemistry Chapter 15 is dedicated to ‘Polymers’ and their use in various areas. Different applications rely on mechanical qualities such as tensile strength, elasticity, toughness, etc. Intermolecular interactions, such as van Der Waals forces and hydrogen bonds in the Polymer, regulate these mechanical properties.
The polymer chains are likewise held together by these forces. As a result, polymers are divided into four sub-groups based on the magnitude of their intermolecular forces.
Students will learn about two different forms of polymerisation reactions in CBSE NCERT Solutions Class 12 Chemistry Chapter 15. Polymers constitute the backbone of five key industries, according to the NCERT Class 12 Chemistry Chapter 15:
- Plastic
- Elastomers
- Fibres
- Paints
- Varnishes
Key Topics Covered in NCERT Solutions Class 12 Chemistry Chapter 15
The Chapter covers the process of creating polymers from monomers and synthesising them. Polymers, monomers, and polymerisation are all explained there.
After that, it looks for distinctions between polymer Classes and different types of polymerisation methods. It also emphasises the construction of polymers from monomers and bifunctional polymers. Finally, it discusses the utilisation of polymers and their applications in everyday life. Students can use NCERT Solutions for Class 12 Chemistry Chapter 15 to complement their Board Examination studies and prepare for competitive Examinations as well.
The concepts of Monomer, Polymer, and Polymerisation are covered in NCERT Solutions for Class 12 Chemistry Chapter 15.
Classification of Polymers based on source:
- Natural Polymers
- Semi-synthetic Polymers
- Synthetic Polymers
Classification of polymers based on structure:
- Linear Branched-chain
- Cross-linked or Network Polymers
Classification of polymers based on polymerisation mode:
- Addition Polymers
- Condensation Polymers.
The following topics are covered in NCERT Solutions for Class 12 Chemistry Chapter 15:
- Polymer Classification
- Polymerisation Reaction Types
- Polymer Molecular Mass
- Biodegradable Polymers
- Commercially Important Polymers
NCERT Solutions Class 12 Chemistry Chapter 15: Marks Weightage
| Unit Name | Marks Weightage |
| Polymers | 3 |
Polymers constitute three questions that are commonly asked in Board Examinations. One question is derived from the one-mark type replies. The other two questions are of the short answer variety. So, three marks’ worth of questions can be derived from this Chapter.
Extramarks recommend students study Polymer at the near end of the course. It has a lot of important definitions, yet it can be completed efficiently and quickly. Students can use NCERT Solutions for Class 12 Chemistry Chapter 15 to boost their overall productivity and preparedness and score well in the finals.
Important Questions from NCERT Solutions Class 12 Chemistry Chapter 15
- Make a distinction between condensation and addition polymerisation.
- For Nylon-6,6, write the monomeric repeating units.
- Define synthetic polymers and natural polymers, and give two examples.
- Explain how ethylene glycol is converted into dacron.
- What is the definition of copolymerisation? Please give an example.
- Give examples of the differences between thermosetting polymers and thermoplastics.
- What are Biodegradable Polymers, and how do they work?
- What does the designation “6, 6” signify in “nylon 6, 6”?
- What are two important Bakelite applications?
- Give the names of the polymers that are employed in laminated sheets, as well as the monomeric units that are involved in their creation.
NCERT Solutions Class 12 Chemistry Chapter 15: Exercises & Solutions
Students can use Polymers Class 12 NCERT Solutions to broaden their knowledge and skills. Solving the NCERT problems for Class 12 Chemistry Chapter 15 helps remove any doubts they may have about the Chapter’s topics. This post will provide you with fully solved NCERT Solutions for Class 12 Chemistry Chapter 15 prepared by Extramarks experts.
Extramarks professionals have carefully curated Chapter 15 NCERT Solutions Class 12 Chemistry by following the latest CBSE syllabus. Students in Class 12 usually feel pressured to perform well in the Board Examinations. NCERT Solutions for Class 12 Chemistry Chapter 15 can come in handy to overcome that and score admirably on the Board Examinations.
Access to the links can be found below:
NCERT Solutions Class 12 Chemistry Chapter 15 Ex 15.1
NCERT Solutions Class 12 Chemistry Chapter 15 Ex 15.2
NCERT Solutions Class 12 Chemistry Chapter 15 Ex 15.3
NCERT Solutions Class 12 Chemistry Chapter 15 Ex 15.4
NCERT Solutions Class 12 Chemistry Chapter 15 Ex 15.5
Our subject experts create NCERT Solutions to assist students in understanding concepts more quickly and correctly. NCERT Solutions provide comprehensive, step-by-step Solutions to textbook problems. The Solutions are available for all Classes.
NCERT Solutions Class 1
NCERT Solutions Class 2
NCERT Solutions Class 3
NCERT Solutions Class 4
NCERT Solutions Class 5
NCERT Solutions Class 6
NCERT Solutions Class 7
NCERT Solutions Class 8
NCERT Solutions Class 9
NCERT Solutions Class 10
NCERT Solutions Class 11
NCERT Solutions Class 12
Advantages of NCERT Solutions Class 12 Chemistry Chapter 15
There are numerous benefits to completing NCERT Polymer Class 12 Solutions. The Solutions are separately divided into two sections:
- Short answers
- Long answers
The answers are delivered in a clear, direct, and accurate manner. Subject specialists at Extramarks ensure that the solutions supplied are of high quality. Diagrams are provided wherever necessary to highlight the important topics. There are also comparison tables that make it simple to compare any two parameters.
How to Study for CBSE Class 12 Chemistry Chapter 15?
NCERT Solutions, prepared by Extramarks for Class 12 Chemistry Chapter 15 Polymers, will assist you in resolving any doubts you may have about any of the Chapter’s practice questions. If you get stuck while answering questions from your textbook, you can look up the answers here. Before attempting the questions, make sure you’ve read the chapter thoroughly and clearly understand all the topics.
To help you with your studies, Extramarks offers free Polymers practise questions and a Class 12 Chemistry Chapter 15 mock test. However, before moving on to these resources, we recommend that you finish our NCERT solutions to facilitate these tests.
NCERT Exemplar Class 12 Chemistry
Students can use NCERT Class 12 Chemistry Exemplars for further assistance with their CBSE Class 12 Examinations and Graduate Admission Tests. NCERT Exemplar for Class 12 Chemistry includes solved Chapter-by-Chapter questions to help students review the entire syllabus quickly.
Students can improve their understanding of the subject by practising problems from this guide. Extramarks’ subject expert team answers all the questions under the NCERT syllabus criteria (2022-2023).
Q.1 Explain the terms polymer and monomer.
Ans.
Polymers are high molecular mass macromolecules composed of repeating structural units derived from monomers. Polymers have a high molecular mass (103 – 107 u). In a polymer, various monomer units are joined by strong covalent bonds. Polymers can be natural as well as synthetic. Polythene, rubber, and nylon 6, 6 are examples of polymers.
Monomers are simple, reactive molecules that combine with each other in large numbers through covalent bonds to give rise to polymers. For example, ethene, propene, styrene, vinyl chloride.
Q.2 What are natural and synthetic polymers? Give two examples of each type.
Ans.
Natural polymers are polymers that are found in nature. They are formed by plants and animals. Examples include protein, cellulose, starch, etc. Synthetic polymers are polymers made by human beings. Examples include plastics (polythene), synthetic fibres (nylon 6, 6), synthetic rubbers (Buna − S).
Q.3 Distinguish between the terms homopolymer and copolymer and give an example of each.
Ans.
| S. No. | Homopolymer | Copolymer |
| (i) | The polymers that are formed by the polymerisation of a single monomer are known as homopolymers. In other words, the repeating units of homopolymers are derived only from one monomer. | The polymers whose repeating units are derived from two types of monomers are known as copolymers. |
| (ii) | For example, polythene is a homopolymer of ethene . | For example, Buna−S is a copolymer of 1, 3-butadiene and styrene. |
Q.4 How do you explain the functionality of a monomer?
Ans.
The functionality of a monomer is the number of binding sites that is/are present in that monomer.
For example, the functionality of monomers such as ethene and propene is one and that of 1, 3-butadiene and adipic acid is two.
Q.5 Define the term polymerisation.
Ans.
Polymerisation is the process of forming high molecular mass (103 – 103u) macromolecules, which consist of repeating structural units derived from monomers. In a polymer, various monomer units are joined by strong covalent bonds.
Q.6 Is (–NH – CHR – CO)n, a homopolymer or copolymer?
Ans.
(–NH – CHR – CO)n is a homopolymer because it is obtained from a single monomer unit, NH2−CHR−COOH.
Q.7 Why do elastomers posssess elastic properties?
Ans.
In elastomers, the polymer chains are held together by weak intermolecular forces which allow them to be stretched. Moreover, a few cross-links between the polymer chains allows them to retract when the forces are withdrawn. Thus, elastomers possess elastic properties.
Q.8 How can you differentiate between addition and condensation polymerisation?
Ans.
| S. No. | Addition polymerisation | Condensation polymerisation |
| (i) | It is the process of repeated addition of monomers, possessing double or triple bonds to form polymers. | It is the process of formation of polymers by repeated condensation reactions between two different bi-functional or tri-functional monomers. A small molecule such as water or hydrochloric acid is eliminated in each condensation. |
| (ii) | For example, polythene is formed by addition polymerisation of ethene.
|
For example, nylon 6, 6 is formed by condensation polymerisation of hexamethylenediamine and adipic acid.
|
Q.9 Explain the term copolymerisation and give two examples.
Ans.
Monomers from two or more different monomeric units is called copolymerisation. Multiple units of each monomer are present in a copolymer. The process of forming polymer Buna−S from 1, 3-butadiene and styrene is an example of copolymerisation
Nylon 6, 6 is also a copolymer formed by hexamethylenediamine and adipic acid.
Q.10 Write the free radical mechanism for the polymerisation of ethene.
Ans.
Polymerisation of ethene to polythene consists of heating or exposing to light a mixture of ethene with a small amount of benzoyl peroxide as the initiator.
The reaction involved in this process is given below:
Q.11 Define thermoplastics and thermosetting polymers with two examples of each.
Ans.
Thermoplastic polymers are linear (slightly branched) long chain polymers, which can be repeatedly softened and hardened on heating. Hence, they can be modified again and again. Examples include polythene and polystyrene. Thermosetting polymers are cross-linked or heavily branched polymers which get hardened during the molding process. These plastics cannot be softened again on heating. Examples of thermosetting plastics include bakelite and urea-formaldehyde resins.
Q.12 Write the monomers used for getting the following polymers.
(i) Polyvinyl chloride (ii) Teflon (iii) Bakelite
Ans.
(i) Vinyl chloride (CH2 = CHCl)
(ii) Tetrafluoroethylene (CF2 = CF2)
(iii) Formaldehyde (HCHO) and phenol (C6H5OH)
Q.13 Write the name and structure of one of the common initiators used in free radical addition polymerisation.
Ans.
One common initiator used in free radical addition polymerisation is benzoyl peroxide. Its structure is given below:
Q.14 How does the presence of double bonds in rubber molecules influence their structure and reactivity?
Ans.
Natural rubber is a linear cis-polyisoprene in which the double bonds are present between C2 and C3 of the isoprene units.
Because of this cis-configuration, intermolecular interactions between the various strands of isoprene are quite weak. As a result, various strands in natural rubber are arranged randomly. Hence, it shows elasticity.
Q.15 Discuss the main purpose of vulcanisation of rubber.
Ans.
Natural rubber though useful has some problems associated with its use. These limitations are discussed below:
1. Natural rubber is quite soft and sticky at room temperature. At elevated temperatures (> 335 K), it becomes even softer. At low temperatures (< 283 K), it becomes brittle. Thus, to maintain its elasticity, natural rubber is generally used in the temperature range of 283 K-335 K.
2. It has the capacity to absorb large amounts of water.
3. It has low tensile strength and low resistance to abrasion.
4. It is soluble in non-polar solvents.
5. It is easily attacked by oxidising agents.
Vulcanisation of natural rubber is done to improve upon all these properties. In this process, a mixture of raw rubber with sulphur and appropriate additive is heated at a temperature range between 373 K and 415 K.
Q.16 What are the monomeric repeating units of Nylon-6 and Nylon-6, 6?
Ans.
The monomeric repeating unit of nylon 6 is [NH – (CH2)5 – CO], which is derived from caprolactam. The monomeric repeating unit of nylon 6, 6 is [NH – (CH2)6 – NH – CO – (CH2)4 – CO], which is derived from hexamethylene diamine and adipic acid.
Q.17 Write the names and structures of the monomers of the following polymers:
(i) Buna-S (ii) Buna-N
(iii) Dacron (iv) Neoprene
Ans.
| Polymer | Monomer | Structure of monomer | |
| (i) | Buna-S | 1, 3-butadiene | CH2 = CH-CH=CH2 |
| Styrene | C6H5CH=CH2 | ||
| (ii) | Buna-N | 1, 3-butadiene | CH2 = CH-CH=CH2 |
| Acrylonitrile | CH2 =CH-CN | ||
| (iii) | Dacron | Ethylene glycol | HOH2C-CH2OH |
| Terephthalic acid |  |
||
| (iv) | Neoprene | Chloroprene |  |
Q.18 Identify the monomer in the following polymeric structures.
Ans.
(i) The monomers of the given polymeric structure are decanoic acid [HOOC – (CH2)8 – COOH] and [H2N(CH2)6NH2] hexamethylene diamine.
(ii) The monomers of the given polymeric structure are
Q.19 How is dacron obtained from ethylene glycol and terephthalic acid?
Ans.
The condensation polymerisation of ethylene glycol and terephthalic acid leads to the formation of dacron.
Q.20 What is a biodegradable polymer? Give an example of a biodegradable aliphatic polyester.
Ans.
A polymer that can be decomposed by bacteria is called a biodegradable polymer. Poly-β-hydroxybutyrate-co-β- hydroxyvalerate (PHBV) is a biodegradable aliphatic polyester.
Related Chapters
FAQs (Frequently Asked Questions)
1. What should I do to prepare for Chapter 12-Polymers?
It would be best to go through the Chapter several times to comprehend the concepts thoroughly. Make a list of all the important definitions after preparing the Chapter. There are a lot of purposes and important terminologies stated in this Chapter. These concepts and terms should not be taken lightly.
Students should complete the course quickly and should revise their learnings with the NCERT Solutions Class 12 Chemistry Chapter 15. These NCERT Solutions will be highly beneficial to students to achieve high results in their Board Examinations. They can also use these papers to hone their skills in preparation for upcoming competitive tests.
2. What are Polymer Classes in Class 12 Chemistry Chapter 15?
Polymers are chains made of unspecified monomeric units. The three main categories of polymers are Thermoplastics, Thermosets, and Elastomers. Looking at how these groups react to heat is the easiest method to tell them apart. Thermoplastic polymers can be amorphous or crystalline. Although they are typically weak, they have rather adaptable behaviour. A thorough understanding of these polymers, as well as the topics surrounding them, is essential.
3. What are free radicals, and what do they do?
Free radicals are atoms or molecules with an odd (unpaired) number of electrons. They are formed when oxygen reacts with specific chemicals. Free radicals are necessary for life and are used by our cells to kill germs that invade our bodies. It can exist independently because it possesses one or more unpaired electrons in its valence shell or outer orbit. The odd number of electrons in a free radical makes it unstable, short-lived, and highly reactive.
4. Why should I use Extramarks NCERT Solutions Class 12 Chemistry Chapter 15?
Extramarks topic experts produce Chapter-by-Chapter and exercise-by-exercise solutions to aid students in their Board Examination preparation. Each solution is created with the utmost care, taking into account the students’ comprehensive abilities. Students’ confidence is boosted by using primary and straightforward language to convey complex ideas. Students can browse through a list of links to Solutions anytime.
5. What is the definition of a Monomer Class 12?
A Monomer is a molecule from any family of primarily organic compounds that can mix with other molecules to form larger molecules called Polymers. A critical property is a monomer’s polyfunctionality, or ability to create chemical interactions with at least two different monomer molecules. By checking the smallest repeating structure first, we can find monomers. The next step is to determine whether or not each carbon atom in the repeating structure contains an octet.
