Problem 11 - A Complete Resource Book in Chemistry for JEE Main

Question

Teflon, styrene and neoprene are all (a) monomers (b) co-polymers (c) homopolymers (d) condensation polymers

Step-by-Step Solution

Answer

(c) homopolymers fits Teflon and neoprene.

Step 1: Understand the Definitions

Before attempting to classify Teflon, styrene, and neoprene, it's important to understand the definitions of the options. Monomers are small molecules that can bind with identical molecules to form a polymer. Co-polymers are polymers made from two different monomers. Homopolymers are polymers made from only one type of monomer. Condensation polymers form by reactions that release a small molecule, such as water, when monomers join.

Step 2: Identify Each Substance

Teflon is a polymer made from the monomer tetrafluoroethylene, making it a homopolymer. Styrene is not a polymer; it is a monomer used to create polystyrene and other co-polymers. Neoprene is a polymer formed from chloroprene and is a homopolymer.

Step 3: Classify the Substances

Based on the definitions and identification, Teflon is a homopolymer, styrene is a monomer, and neoprene is a homopolymer. None of these are co-polymers or condensation polymers as defined. Thus, they do not all belong to the same classification category listed.

Step 4: Select the Correct Answer

From the analysis, only styrene is a monomer. Teflon and neoprene are homopolymers. Hence, none of the options fit all three substances perfectly, as option (c) homopolymers fits two but not styrene, which is a monomer.

Key Concepts

Monomers in Polymer Chemistry

Monomers are the building blocks of polymers. They are small, simple molecules that have the unique ability to bond with other identical molecules to form long chains. These chains are what we call polymers. A monomer contains specific reactive sites that allow it to connect with others, like pieces of a puzzle.

Monomers come in various types, with each one leading to different polymers:

• Saturated Monomers: These form addition polymers where there are no small molecules released in the process.
• Unsaturated Monomers: Typically involve a reaction where small byproducts are released, like in condensation polymers.

For instance, styrene, a monomer, connects to form polystyrene — a widely used plastic. Understanding monomers is crucial as they determine the properties and applications of the resultant polymer.

Co-polymers: A Blend of Monomers

Co-polymers form when two different types of monomers bind together to create a polymer. This special combination leads to materials with unique properties that aren't present when using a single type of monomer.

Co-polymers can adopt various configurations depending on how the monomers are arranged:

• Random Co-polymers: Monomers are distributed randomly along the chain.
• Alternating Co-polymers: Two different monomers alternate positions in the chain.
• Block Co-polymers: Segments of one type of monomer followed by another.

These structures define the physical and chemical characteristics of co-polymers, offering flexibility in applications from clothing to automotive parts.

Understanding Homopolymers

Homopolymers are composed entirely of one type of monomer. They represent a simpler class of polymers compared to co-polymers. Despite this simplicity, homopolymers can possess specialized properties that make them highly valuable.

Some common examples include:

• Polyethylene: Derived from ethylene monomers, used in plastic bags and bottles.
• Teflon: Created from tetrafluoroethylene monomers, known for its non-stick property.
• Neoprene: Originating from chloroprene monomers, appreciated for its elasticity and strength.

Homopolymers are often favored when uniformity in properties is desired.

Exploring Condensation Polymers

Condensation polymers are unique in that their formation involves a chemical reaction where small molecules, often water or methanol, are byproducts. This occurs during the joining of monomers, making the process distinct from other polymer types.

Key examples include:

• Nylons: Common in textiles, created through reactions releasing water.
• Polyesters: Popular in clothing and packaging, also formed with water release.

Understanding condensation polymers is vital because they differ greatly in their formation and applications compared to addition polymers, which do not release byproducts.