Answer

(d) Glycogen is a polymer of glucose found in liver, brain and muscles of animals.

Cellulose is a polymer found in plant while amylose and amylopectin are structural units of starch.

Answer

(a) cis-polyisoprene is not a semisynthetic polymer while other three cellulose nitrate, cellulose acetate and vulcanised rubber are semisynthetic polymer made from cellulose, cellulose and natural rubber respectively.

Answer

(b) The commercial name of polyacrylonitrile is orlon (acrilan).

Answer

(c)

Poly $\beta$ - hydroxybutyrate - co- $\beta$ - hydroxy valerate is an example of biodegradable polymer.

Answer

(a) Given polymer can be obtained condensation polymerisation of ethylene glycol and phthalic acid with the elimination of water molecule.

Answer

(d) Low density polythene has slightly branched but not highly branched structure.

Answer

can be obtained by addition polymerisation of

shown below

Answer

(d) Given, monomer is the structure of caprolactum which on polymerisation produces Nylon-6.

Answer

( $b, c$ )

Buna-S and neoprene are two such polymers which needs atleast one diene monomer for their preparation.

(b) Buna-S is prepared by copolymerisation of 1, 3-butadiene and styrene.

(c) Neoprene is prepared by polymerisation of chloroprene

Answer

(a, c)

Thermosetting polymer

(i) These are cross linked or heavily branched molecule.

(ii) These on heating undergo extensive cross linking in moulds and become infusible

(iii) These cannot be reused.

(iv) Examples are bakelite, urea-form aldehyderesin.

Answer

$(a, d)$ Thermoplastic polymer

(i) These are linear or slightly branched long chain molecules.

(ii) These polymers are hard at room temperature, become soft and viscous on heating and again rigid on cooling. This process of heat softening and hardening on cooling can be repeated as many times and as desired without any change in chemical composition.

Answer

(c, d)

Nylon and terylene are used as fibre due to strong intermolecular forces like $\mathrm{H}$-bonding which lead to close packing in chain and thus impart crystalline nature.

Answer

(c, d)

Addition polymers are formed by the repeated addition of a large number of same or different monomers possessing double and triple bonds.

e.g.,

(i) Orlon is obtained by addition polymerisation of acrylonitrile in presence of a perovide catalyst.

(ii) Polystyrene is obtained by addition polymeriration of styrene.

Answer

$(a, d)$

Condensation polymers are formed by repeated condensation reaction between two bifunctional or trifunctional monomer units usually with the elimination of small molecules like water, alcohol, ammonia, $\mathrm{CO} _{2}, \mathrm{HCl}$.

e.g.,

(i) Bakelite is obtained by polymeristation of phenol and formaldehyde.

(ii) Melamine-formaldehyde resin

Answer

( $a, b$ )

Biodegradable Polymer The polymers which are easily decomposed and not harmful for the environment are known as biodegradable polymer.

e.g.,

(i) PHBV is obtained by condensation polymerisation of 3 hydroxybutanoic acid and 3 hxydroypentanoic acid.

(ii) Glycine and aminocaproic acid produces nylon-2 nylon-6 polymer.

Answer

$(a, c)$

Synthetic Polymer Polymer which are not found in nature and can be synthesised in laboratory and industry are known as synthetic polymer.

e.g.,

(i) Polychloroprene also known as neoprene is a polymer of chloroprene [monomer].

(ii) Buna- $\mathrm{N}$ can be obtained by copolymerisation of 1, 3-Butadiene and acyrlonitrile as shown below

Answer

$(a, d)$

Nylon and polyesters have strong intermolecular forces of attractions due to presence of ether $\mathrm{H}$-bonding or dipole-dipole interactions.

Answer

$(a, b, d)$

Acrilan, polystyrene and teflon has vinylic monomer units as shown below.

Thinking Process

This problem includes the concept of vulcaniztion of rubber and characteristic of vulcanized rubber. Vulcanization of rubber produces more elastic and more stiff rubber due to presence of sulphide linkage.

Answer

$(a, d)$

In vulcanized rubber, the polymer chains are held together by sulphur cross- linkages ( - S-S - ). These cross links make rubber more hard, elastic and stronger.

Thinking Process

This problem is based on vulcanized rubber and its structure.

Answer

The product is called vulcanised rubber. Its structure is

Answer

Homopolymer as it contains only one type of monomer units. i.e., only A monomer units.

Answer

Copolymer, as it contains more than one type of monomer units. Here, $A$ and $B$ are two types of monomer units.

Answer

Chain growth polymerisation, as there is no loss of small molecules like water; methanol etc.

Answer

Cross-linked or network polymer.

Answer

The given polymer is formed by’, 1, 4–addition of 2- methylbuta- 1,3-diene (isoprene) and stereochemistry is ‘cis’ throughout. Therefore, the given polymer is ‘cis’- polyisoprene i.e., natural rubber.

Answer

They change their shape on applying force and regain their original shape on removal of the applied force. Hence, rubbers are called elastomers.

Answer

Yes, these are made up of proteins which are polymers of amino acids.

Answer

Yes, nucleic acid, protein and starch can be considered as step growth polymers as during their polymerisation reaction, they lead to removal of water molecule or any neutral molecule also. Thus, these are the examples of condensation polymers or step growth polymerisation.

Answer

Reaction between melamine and formaldehyde can be shown as

Melamine-formaldehyde polymer is formed by this monomer unit.

Answer

Cross links in rubber required for increasing the elasticity of rubber.

Answer

cis-polyisoprene is also known as natural rubber. Its elastic property is due to the existence of weak van der Waals’ interactions between their various polymer chains.

Answer

HDP (high density polymer) consists of linear molecule and has a high density due to close packing. It is a translucent polymer. While LDP (low density polymer) has highly branched structure and hence, does not pack well resulting in low density. It is a transparent material.

Answer

Role of benzoyl peroxide is to initiate the free radical polymerization reaction which can be easily understood by taking an example of polymerization of ethene to polyethene.

Answer

Strong intermolecular forces like hydrogen bonding and linear structure that lead to close packing of chains and hence, imparts crystalline character. e.g., nylon

Answer

Urea formaldehyde resin is used for laminated sheets. The monomer of this resin is urea $\left(\mathrm{NH} _{2} \mathrm{CoNH} _{2}\right)$ and formaldehyde $(\mathrm{HCHO})$

Answer

Polyamides have structural repeatation of amide linkages which is similar to peptide bond as present in polypeptide chains of proteins.

Answer

During free radical polymerisation, monomers should be very pure because even very trace amounts of impurities may act as inhibitors which leads to the formation of polymers with shorter length.

Answer

A. $\rightarrow$ (5)

B. $\rightarrow$ (3)

C. $\rightarrow(1)$

D. $\rightarrow(2)$

E. $\rightarrow(4)$

Column I represents various kind of polymer and Column II represents their monomer units. Correct matching can be done as

Answer

A. $\rightarrow(3)$

B. $\rightarrow(1)$

C. $\rightarrow(2)$

D. $\rightarrow(5)$

E. $\rightarrow(4)$

Column I represents various polymers and Column II represents their chemical names.

Answer

A. $\rightarrow$ (2)

B. $\rightarrow(3)$

C. $\rightarrow(1)$

D. $\rightarrow(5)$

E. $\rightarrow(4)$

Column I represents monomers of polymer and Column II represents their commercial name.

Answer

A. $\rightarrow(4)$

C. $\rightarrow(1)$

E. $\rightarrow(4)$

Answer

A. $\rightarrow$ (4)

B. $\rightarrow(1)$

C. $\rightarrow(2)$

Column I represents name of various polymer and Column II represents mechanism of polymerisation. Correct matching can be done as

Answer

A. $\rightarrow(2)$

B. $\rightarrow(4)$

C. $\rightarrow(1)$

D. $\rightarrow(4)$

E. $\rightarrow$ (3)

Column I represents name of polymer and Column II represents types of linkage. Hence, correct matching can be done as

Answer

A. $\rightarrow(6)$

B. $\rightarrow(5)$

C. $\rightarrow(1)$

D. $\rightarrow$ (3)

E. $\rightarrow$ (2)

F. $\rightarrow(4)$

Column I represents various uses or precursurs of polymers and Column II represents name of related polymer. The correct matching can be done as

Answer

A. $\rightarrow(4)$

B. $\rightarrow(1)$

C. $\rightarrow(2)$

D. $\rightarrow(4)$

E. $\rightarrow(3)$

Column I represents name of polymer and Column II represents their molecular formula. The correct matching can be done as

Answer

(b) Assertion and reason both are correct and reason explains the assertion.

Rayon is a semisynthetic polymer and is taken as a better choice than cotton fabric because mechanical and aesthetic properties of cellulose can be improved by acetylation

Answer

(d) Assertion is correct statement but reason is not correct statement. Most of synthetic polymers are not biodegradable because they are not easily broken by soil organisms and hazardous to the environment.

Answer

(a) Assertion and reason both are correct but reason does not explain assertion. Olefin monomers undergo addition polymerisation because it add on to other monomers of olefin through free radical mechanism due to the presence of peroxide initiator and double bond and produces high molecular mass polymers.

Answer

(b) Assertion and reason both are correct and reason explains assertion. Polyamides are best used as fibres because of high tensile strength. This is due to strong intermolecular forces (like hydrogen bonding within polyamides) lead to close packing of chains and increase the crystalline character, hence, provide high tensile strength to polymers.

Answer

(e) Assertion is wrong and reason is correct statement. Correct assertion is, neoprene is a naturally occurring polymer of chloroprene prepared by polymerisation of 2-chloro butadiene.

Answer

(a) Assertion and reason both are correct and reason does not explain assertion. Network polymers are thermosetting because they can’t be reused after heating once. Because after heating it undergo extensive cross linking in moulds and again become infusible.

Answer

(a) Assertion and reason both are correct but reason does not explain assertion.

Polytetrafluoroethene (teflon) is used in making non-stick cookwares because it is chemically inert, thermally stable and resistant to attack by corrosive reagents.

Answer

Synthetic polymers are quite resistant to environmental degradation process and are responsible for accumulation of polymer solid waste material. New biodegradable synthetic polymers have been designed and developed. These polymers contain similar functional groups as present in biopolymers. e.g., aliphatic polyesters

Biopolymer, are polymers of amino acid or carbohydrates which are linked to each other by peptide or glycosidic linkages as shown below

Starch (polymer of glucose)

Biopolymer can or can’t be biodegradable.

e.g., protein, starch etc, are biodegradable but keratin are non-biodegradable.

Biodegradable polymer are polymers which can be degradable always.

e.g., DHBV nylon-2, Nylon-6

Answer

Rubber is a natural polymer which possess elastic properties. Natural polymer is a linear polymer of isoprene (2-methyl-1, 3-butadiene).

In natural rubber cis-polyisoprene molecules consists of various chains held together by weak van der Waals’ interaction and has coiling structure. So, it can be stretched like a spring.

Plastics are generally polymer of ethene known as polythene. Polythene is thermoplastic polymer which may be linear (HDP) or branched (LDP) these type of polymers. Possesses intermediate intermolecular forces of attraction. It has linear, structure that can be moulded but can’t be regained on its original shape after stretching.

Answer

Phenol and formaldehyde undergo condensation to give a polymer novolac $(A)$ which on heating with formaldehyde gives bakelite $(B)$ as a thermosetting polymer.

Sequence of the reaction can be written as

Structural difference in between these two is that novolac is a linear polymer while bakelite is a cross linked polymer.

Answer

Low density and high density polythenes are obtained under different conditions. These differ in their structural features. Low density polythenes are highly branched structures while high density polythene consists of closely packed linear molecules. Close packing increases the density.

Answer

Polythene, polyvinyls and polystyrene soften on heating and harden on cooling. Such polymers are called thermoplastic polymers. These polymers are linear array of slightly branched long chain molecules.

These possess intermolecular forces whose strength lies between strength of intermolecular forces of elastomers and fibres while bakelite, urea formaldehyde resin are thermosetting polymers which on heating undergo extensive cross linking in moulds and again become infusible.