Problem 114 - A Complete Resource Book in Chemistry for JEE Main

Question

Match the following: List I List II (Polymer) \(\quad\) (Polymerizing units) 1\. Bakelite (i) Butadiene and styrene 2\. Dacron (ii) Phenol and methanal 3\. Nylon-66 (iii) 1,2 -dihydrooxyethane and dimethyl terephthalate 4\. Buna-S (iv) Urea and methanal (v) 1 , 6-hexanedioic acid and 1,6 -diamino hexane The correct matching is: \(\begin{array}{llll}1 & 2 & 3 & 4\end{array}\) (a) (iii) (v) (ii) (iv) (b) (ii) (iii) (iv) (i) (c) (iv) (iii) (v) (i) (d) (ii) (iii) (v) (i)

Step-by-Step Solution

Answer

The correct matching is option (d).

Step 1: Understand Bakelite

Bakelite is a polymer formed from phenol and formaldehyde (methanal). This means that the polymerizing units for Bakelite are phenol and methanal. Thus, matches to (ii).

Step 2: Understand Dacron

Dacron, also known as PET (polyethylene terephthalate), is a polymer made from the polymerizing units 1,2-dihydroxyethane (ethylene glycol) and dimethyl terephthalate. Therefore, Dacron matches to (iii).

Step 3: Understand Nylon-66

Nylon-66 is a type of nylon synthesized from hexanedioic acid (adipic acid) and 1,6-diamino hexane (hexamethylenediamine). Thus, it matches to (v).

Step 4: Understand Buna-S

Buna-S is a copolymer made from butadiene and styrene, a synthetic rubber. Therefore, Buna-S matches to (i).

Step 5: Match the Pairs Carefully

Based on the above analysis, we can match the polymers from List I with their polymerizing units in List II as follows: 1. Bakelite - (ii) Phenol and methanal 2. Dacron - (iii) 1,2-dihydroxyethane and dimethyl terephthalate 3. Nylon-66 - (v) 1,6-hexanedioic acid and 1,6-diamino hexane 4. Buna-S - (i) Butadiene and styrene

Step 6: Find the Correct Option

From the matching in Step 5, the corresponding option is: (d) (ii), (iii), (v), (i).

Key Concepts

Bakelite

Bakelite is one of the first synthetic plastics ever created, discovered by Belgian chemist Leo Baekeland in 1907. It is a thermosetting phenolic resin that forms through a condensation reaction between phenol and formaldehyde, also known as methanal. Unlike thermoplastics, Bakelite does not melt when heated, l because its structure transforms to a hard, irreversible state.

Uses of Bakelite:

• Electrical insulators
• Handles for kitchenware
• Casings for radios and telephones

These uses are attributed to Bakelite's excellent electrical insulation properties and high heat resistance, making it a valuable material during the early 20th century industrial era.

Dacron

Dacron, more commonly known as polyethylene terephthalate (PET), is a type of polyester formed by polymerizing units of 1,2-dihydroxyethane (ethylene glycol) and dimethyl terephthalate. The polymerization process involves a reaction that releases small byproducts, creating a durable fiber known for its strength and resilience.

Key Properties of Dacron:

• Highly resistant to wrinkles and shrinking
• Strong and durable
• Moisture-wicking and quick-drying

This combination of properties makes Dacron ideal for manufacturing clothing textiles, particularly in activewear and outdoor gear, where fabric durability is crucial.

Nylon-66

Nylon-66 is a prominent member of the nylon family, a type of synthetic polyamide. It is synthesized by the condensation reaction between hexanedioic acid (adipic acid) and 1,6-diamino hexane (hexamethylenediamine). The '66' in Nylon-66 refers to the six carbon atoms from each of its two monomers used in the formation of the polymer chain.

Characteristics of Nylon-66:

• High melting point
• Superior abrasion resistance
• Excellent tensile strength

These qualities make Nylon-66 a popular choice for manufacturing high-performance materials, including automotive components, industrial machinery, and textile products like ropes and nets.

Buna-S

Buna-S, also known as Styrene Butadiene Rubber (SBR), is a synthetic rubber copolymer consisting of styrene and butadiene. The material is created through a polymerization process that combines these two monomers in varying proportions, providing flexibility in tailoring the rubber's properties to different applications.

Features of Buna-S:

• Good abrasion resistance
• Durability while maintaining flexibility
• Resistance to aging and cracking

Because of its cost-effectiveness and resilience, Buna-S is widely used in the manufacture of automobile tires, shoe soles, and even some rubberized flooring materials.