Polymers

Step 1: Identify polymer type.
Terylene (PET) is a polyester formed by condensation of terephthalic acid and ethylene glycol, containing repeated (ester) linkages.
Step 2: Eliminate others.
Nylon: polyamide ( ) linkages.
Teflon: addition polymer of , no ester.
Bakelite: phenol–formaldehyde resin (ether/methylene bridges), no ester.
Step 3: Conclusion.
Hence, Terylene contains ester linkages.

Step 1: Define thermosetting plastics.
Thermosetting plastics are polymers that irreversibly harden when heated and cannot be remoulded. They form cross-linked structures.
Step 2: Analyze options.
- Nylon 6 and Nylon 6,6 are polyamides (thermoplastics).
- P.V.C. is a thermoplastic polymer.
- Bakelite is a phenol–formaldehyde resin, a thermosetting plastic.
Step 3: Conclusion.
Thus, the correct answer is Bakelite.

Step 1: Recall definition.
Polyamides are polymers containing (amide) linkages.
Step 2: Analyze options.
- Teflon: poly(tetrafluoroethylene), no amide linkage.
- Nylon 6,6: condensation polymer of adipic acid and hexamethylenediamine → contains amide linkages.
- Terylene: polyester, contains ester linkages.
- Bakelite: phenol–formaldehyde resin, no amide linkage.
Step 3: Conclusion.
Hence, the correct answer is Nylon 6,6.

Step 1: Definition.
Synthetic rubbers are man-made polymers with elastic properties similar to natural rubber. They are obtained by polymerization of various monomers.
Step 2: Examples.
1. Buna-S (Styrene-butadiene rubber): Formed by copolymerization of 1,3-butadiene and styrene.
2. Neoprene: Formed by polymerization of chloroprene (2-chloro-1,3-butadiene).
Step 3: Uses.
- Buna-S is used in automobile tires.
- Neoprene is resistant to oil and chemicals and used for making hoses and gaskets.

Step 1: Recall natural rubber structure.
Natural rubber is obtained from the latex of rubber trees. It is a polymer of isoprene units .
Step 2: Type of polymerization.
It is formed by 1,4-addition polymerization of isoprene, resulting in cis-1,4 polyisoprene.
Step 3: Analysis of options.
(A) Ethylene: Polymerizes to form polyethylene, not rubber.
(B) Benzene: Aromatic, not polymerized to rubber.
(C) Isoprene: Correct — forms natural rubber.
(D) None of these: Incorrect.
Step 4: Conclusion.
Thus, natural rubber is a polymer of isoprene.

(i) Synthetic Polymer:
A synthetic polymer is a polymer that is artificially made by polymerizing small monomer units through chemical processes. Example: Polyethylene (used in plastic bags). Polyethylene is made by polymerizing ethylene (C₂H₄) monomers.
(ii) Condensation Polymer:
A condensation polymer is formed by the reaction between two different monomers, resulting in the elimination of a small molecule like water or alcohol. Example: Nylon-6,6 (used in fabrics). It is made by condensation polymerization of hexamethylene diamine and adipic acid, releasing water as a by-product.

Step 1: Understanding natural rubber.
Natural rubber is a polymer made from the monomer isoprene (2-methyl-1,3-butadiene). It is produced by the latex of rubber trees and is known for its elasticity and resilience. Step 2: Analysis of options.
(A) Isoprene: Correct — Isoprene is the monomer that polymerizes to form natural rubber.
(B) Nitrocellulose: Nitrocellulose is a synthetic polymer and is not natural rubber.
(C) Polyethylene: Polyethylene is a synthetic polymer, not a natural rubber.
(D) Bakelite: Bakelite is a synthetic resin, not a natural rubber.
Step 3: Conclusion.
The correct answer is (A) because isoprene is the building block of natural rubber.

Step 1: Understanding nylon synthesis.
Nylon is a synthetic polymer made through the polymerization of diamines and dicarboxylic acids. The most common raw materials for making nylon are adipic acid and hexamethylenediamine. Step 2: Analysis of options.
(A) Ethylene: Ethylene is not used in the synthesis of nylon. It is used in making polyethylene and other plastics.
(B) Butadiene: Butadiene is used in the production of synthetic rubbers, not nylon.
(C) Adipic acid: Correct — Adipic acid is a key raw material used in the synthesis of nylon. It reacts with hexamethylenediamine to form nylon-6,6.
(D) Isoprene: Isoprene is used in the production of synthetic rubber, not nylon.
Step 3: Conclusion.
The correct answer is (C) because adipic acid is used in the production of nylon.

Step 1: Understanding the structure.
The monomer is the repeating unit of Teflon (polytetrafluoroethylene, PTFE), a polymer known for its high resistance to chemicals and heat. Step 2: Analysis of options.
(A) Teflon: Correct — The polymerization of leads to the formation of Teflon.
(B) Glyptal: Glyptal is a polyester resin used in paints and coatings, and is not made from the given monomer.
(C) Nylon-6: Nylon-6 is made from caprolactam, not from the given monomer.
(D) Buna-S: Buna-S is a synthetic rubber made from butadiene and styrene, not from the given monomer.
Step 3: Conclusion.
The correct answer is (A) because is the monomer for Teflon.

Step 1: Define addition polymerization.
Addition polymerization is a process where monomers with double bonds (unsaturated monomers) add together without losing any atoms, forming long-chain polymers. PVC (Polyvinyl chloride) is a typical product of addition polymerization.
Step 2: Analyze the options.
- PVC (Option A) is made by addition polymerization of vinyl chloride monomers. - Nylon (Option B) is made by condensation polymerization. - Terylene (Option C) is made by condensation polymerization. - Polyamide (Option D) refers to polymers formed by condensation polymerization.
Step 3: Apply to the options.
The correct answer is (A) PVC.
Final Answer:

Step 1: Define thermosetting plastics.
Thermosetting plastics are plastics that harden when heated and cannot be re-melted or re-shaped after the first heating.
Step 2: Analyze the options.
- Bakelite (Option C) is a thermosetting plastic that is formed by the polymerization of phenol and formaldehyde. It hardens permanently after heating and is used for electrical insulators. - PVC (Option A) and PVA (Option B) are thermoplastics, which can be re-melted and re-shaped. - None of these (Option D) is incorrect.
Step 3: Apply to the options.
The correct answer is (C) Bakelite.
Final Answer: