Polymers

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Addition polymers formed by the polymerization of a single monomeric species are known as homopolymers. The above-given polymer is a homopolymer.

This is a short answer type question as classified in NCERT Exemplar

While manufacturing tyre rubber, 5 % sulfur is used as a crosslinking agent. A natural linear polymer of 2-methyl-1, 3-butadiene becomes hard on treatment with sulfur and forms vulcanised rubber. The structure of the product formed is,

This is a multiple choice answer as classified in NCERT Exemplar

Option (A) and (D)

Explanation: Vulcanisation is a process used to improve the physical properties of natural rubber. This method involves heating a mixture of raw rubber, sulphur, and an appropriate additive to temperatures ranging from 373 K to 415 K. Sulphur forms cross links at the reactive sites of double bonds during vulcanisation, stiffening the rubber.

This is a multiple choice answer as classified in NCERT Exemplar

Option (A), (B) and (D)

Explanation: Polyacrylonitrile is formed by the addition polymerisation of acrylonitrile in the presence of a peroxide catalyst. Polyacrylonitrile is used as a wool substitute in the manufacture of commercial fibers such as orlon or acrilan.

Polystyrene has the monomer unit styrene.

Teflon is made by heating tetrafluoroethene at high pressures with a free radical or persulphate catalyst.

This is a multiple choice answer as classified in NCERT Exemplar

Option (A) and (D)

Explanation: Polyamides: These polymers with amide linkages are important examples of synthetic fibers and are known as nylons.

Polyesters: These are the polycondensation products of dicarboxylic acids and diols.

Dacron or terylene is the most well-known example of a polyester.

This is a multiple choice answer as classified in NCERT Exemplar

Option (A) and (C)

Explanation: Synthetic rubbers are either homopolymers or copolymers of 1,3-butadiene or its derivatives with another unsaturated monomer. Polychloroprene or neoprene and Buna-N are examples of synthetic rubber.

This is a multiple choice answer as classified in NCERT Exemplar

Option (A) and (B)

Explanation: The polymers that are not harmful to the environment are biodegradable polymers. PHBV (Poly beta-hydroxybutyrate co-beta-hydroxy valerate) is a biodegradable polymer. It undergoes bacterial degradation in the environment. PHBV is obtained by the polymerization of 3-hydroxybutyric acid and 3-hydroxypentanoic acid.

Nylon-2, Nylon-6 polymers are also biodegradable. It is obtained by the polymerization of glycine and aminocaproic acid.

This is a multiple choice answer as classified in NCERT Exemplar

Option (A) and (D)

Explanation: Condensation polymers are formed by the addition of more than one monomeric unit. Bakelite and Melamine formaldehyde resin are condensation polymers. Bakelite is a polymer formed from phenol and formaldehyde. Melamine formaldehyde resin is a polymer formed from melamine and formaldehyde.

This is a multiple choice answer as classified in NCERT Exemplar

Option (A) and (D)

Explanation: The formation of addition polymers is accomplished through the repeated addition of monomer molecules with double or triple bonds, such as polythene from ethene and polypropene from propene. Homopolymers are addition polymers formed by the polymerisation of a single monomeric species. 

This is a multiple choice answer as classified in NCERT Exemplar

Option (C) and (D)

Explanation: Fibers are thread-forming solids. They possess high tensile strength and high modulus. They have strong intermolecular forces of attraction like hydrogen bonding. Nylon and Terylene are used as fibers.