Problem 2 - A Complete Resource Book in Chemistry for JEE Main

Question

On the basis of mode of formation, polymers can be classified (a) as addition polymers only (b) as condensation polymers only (c) as co-polymers (d) both addition and condensation polymers

Step-by-Step Solution

Answer

(d) both addition and condensation polymers.

Step 1: Understanding Addition Polymers

Addition polymers are formed by the polymerization of monomers with unsaturated bonds (like alkenes), where the monomers add to each other without losing any small molecule. A common example is polyethylene.

Step 2: Understanding Condensation Polymers

Condensation polymers are formed by the reaction between monomers in which they lose small molecules such as water, alcohol, or hydrogen chloride as by-products. Examples include polyester and nylon.

Step 3: Checking Co-polymers

Co-polymers are polymers formed from two or more different monomers. The formation could follow either addition or condensation polymerization, so the mode depends on the specific monomers and polymerization method used.

Step 4: Analyzing the Options

Options (a) and (b) limit classification to only one mode of polymerization (either addition or condensation), while (c) refers to polymer diversity in terms of monomer type, not mode of formation. Option (d) includes both common modes of polymerization, providing the most comprehensive classification basis.

Key Concepts

Understanding Addition Polymers

Addition polymers are formed when monomers with unsaturated carbon bonds join together, without the loss of any atoms or small molecules. A great way to think about this is as a string of beads, where each bead represents a monomer. When you string them together, they form a continuous chain without dropping any beads.

These types of polymers are often created from monomers like alkenes. Alkenes have double bonds, and when they react, they open up these bonds to connect with other molecules. Polyethylene, the kind of plastic you might find in grocery bags or bottles, is an example of an addition polymer. These are popular due to their simplicity and ease of production.

• **Formation:** Direct combination of monomers without small molecules as by-products.
• **Example:** Polyethylene, Polypropylene.
• **Characteristics:** Usually have high tensile strength and are not easily biodegradable.

Exploring Condensation Polymers

Condensation polymers form when monomers react together and lose small molecules as by-products, commonly water, alcohol, or hydrogen chloride. To visualize this, think of two pieces joining together and squeezing out the extra material, like a wet sponge being pressed.

A classic example of a condensation polymer is nylon, a material widely used in clothing and industrial products. Creating these polymers involves reactions where different functional groups, often acids and alcohols, react to form the polymer chain.

• **Formation:** Monomers bond with the elimination of small molecules.
• **Example:** Nylon, Polyester.
• **Characteristics:** Strong and durable, but can be more costly to produce than addition polymers.

What are Co-polymers?

Co-polymers are fascinating because they are made from two or more different types of monomers, allowing for versatile material properties. You can imagine co-polymers as a mix of different colored beads, each color representing a different monomer, joined together in a variety of patterns and sequences.

The combination of monomers in co-polymers can lead to materials with specific characteristics tailored for unique applications. For example, in some cases, they can blend the properties of plastics and rubbers, resulting in products that are flexible yet tough.

• **Formation:** Integration of different monomers, potentially through both addition and condensation processes.
• **Example:** ABS plastic, utilized in toys and appliances for its resilience.
• **Characteristics:** Versatile in use, combining properties of parent monomers to suit varied applications.