Problem 113 - A Complete Resource Book in Chemistry for JEE Main

Question

Match the following: \(\begin{array}{ll}\text { List I } & \text { List II }\end{array}\) 1\. Coordination (i) Polypeptide polymerization 2\. Free radical (ii) Nylon-6, 6 polymerization 3\. Addition (iii) Zeigler-Natta polymerization 4\. Natural rubber (iv) Azobis isobutyronitrile (v) cis-1,4-polyisoprene The correct matching is: 1 2 3 4 (a) (iii) (iv) (ii) (v) (b) (ii) (v) (i) (iv) (c) (iii) (v) (iv) (ii) (d) (i) (iii) (iv)

Step-by-Step Solution

Answer

The correct option is (a) iii, iv, ii, v.

Step 1: Understand the Terms

List I contains terms related to types of polymerization processes or chemical substances involved in polymerization. Coordination, Free radical, Addition, and Natural rubber are these terms. List II provides specific polymerization processes or chemical compounds.

Step 2: Match 'Coordination'

Coordination polymerization is typically associated with the Ziegler-Natta polymerization process. This involves catalysts like titanium chloride and alkyl aluminum, used for synthesizing polymers such as polyethylene and polypropylene. Therefore, the correct match for Coordination is (iii) Ziegler-Natta polymerization.

Step 3: Match 'Free radical'

Free radical polymerization is initiated by substances like Azobis isobutyronitrile, which generate free radicals that drive the polymerization process through a chain reaction. Thus, Free radical matches with (iv) Azobis isobutyronitrile.

Step 4: Match 'Addition'

Addition polymerization can involve processes like the creation of Nylon-6, 6. This reaction involves the formation of polymers by adding monomers without the loss of any small molecules. Consequently, Addition matches with (ii) Nylon-6, 6 polymerization.

Step 5: Match 'Natural rubber'

Natural rubber is primarily composed of cis-1,4-polyisoprene. The polymerization of isoprene leads to the formation of this rubber, which is a naturally occurring polymer. Therefore, Natural rubber corresponds to (v) cis-1,4-polyisoprene.

Step 6: Compile the Complete Match

Now that each item from List I is matched with its respective counterpart in List II, compile the matches: Coordination - (iii), Free radical - (iv), Addition - (ii), Natural rubber - (v).

Key Concepts

Coordination polymerization

Coordination polymerization is a fascinating process that forms long chain molecules or polymers using specialized catalysts. One of the most well-known methods in coordination polymerization is the Ziegler-Natta polymerization. This technique operates with catalysts such as titanium chloride and alkyl aluminum. These catalysts play a crucial role by controlling the orientation and regularity of the polymer chain, which is essential for producing high-quality polymers like polyethylene and polypropylene.

The unique aspect of coordination polymerization is that it allows for the polymer chains to have consistent structural properties. This consistency is important for applications requiring durable plastics, such as in packaging and automotive parts. Coordination polymerization is utilized mainly for polymers that we need in large scale, where precision and stability are key.

• Example Polymers: Polyethylene, Polypropylene
• Main Catalysts: Titanium chloride, Alkyl aluminum
• Key Feature: Control over polymer chain configuration

Free radical polymerization

Free radical polymerization is a type of polymerization process that involves the creation of polymer chains through radical intermediaries. This method uses initiators like Azobis isobutyronitrile, which decompose to form free radicals. These radicals are highly reactive and initiate a chain reaction, leading to the formation of polymers.

The process of free radical polymerization is quite versatile and is used to create a wide variety of polymers. One of its main advantages is the technique's ability to be conducted under simple conditions, both at room and elevated temperatures. It’s particularly suitable for making polymers like polystyrene and polyvinyl chloride (PVC).

• Example Initiator: Azobis isobutyronitrile
• Common Polymers: Polystyrene, PVC
• Process Type: Chain reaction mechanism

Addition polymerization

Addition polymerization is a simple yet incredibly important polymerization method where monomers add together without the loss of atoms in the process. A classic example of this is the formation of polymers like Nylon-6, 6. This process typically occurs with monomers that possess double or triple bonds, leading to the formation of a polyolefin or another polymer.

The key advantage of addition polymerization is its ability to form polymers quickly and efficiently, often using a catalyst or simply heat to start the reaction. It is utilized in the industrial production of many everyday items, from plastics to synthetic fibers.

• Characteristics: No loss of atoms, addition of monomers
• Typical Products: Plastics, Synthetic fibers like Nylon-6, 6
• Common Requirements: Presence of double or triple bonds in monomers

Natural rubber

Natural rubber, a crucial natural polymer, is primarily derived from isoprene, a biochemical precursor. The polymerization of this compound forms cis-1,4-polyisoprene, which constitutes the main component of natural rubber. This type of rubber boasts tremendous elasticity and resilience, making it invaluable in various industrial and consumer applications.

The process of obtaining natural rubber involves tapping rubber trees to collect latex and then processing it into a usable form. Natural rubber, due to its excellent properties, is widely used in products such as tires, footwear, and elastic bands.

• Main Component: cis-1,4-polyisoprene
• Uses: Tires, Shoes, Elastic goods
• Production Method: Harvesting and processing of latex from rubber trees