Problem 10 - A Complete Resource Book in Chemistry for JEE Main

Question

Treatment of rubber with sulphur is (a) annealing (b) vulcanization (c) quenching (d) none of these

Step-by-Step Solution

Answer

The treatment of rubber with sulphur is vulcanization.

Step 1: Understanding the Question

The question is asking about a treatment process for rubber that involves sulphur. We need to identify the correct term for this process from the given options.

Step 2: Identifying the Process

We recall that vulcanization is a chemical process for converting rubber into a more durable material by adding sulphur. This process involves heating the rubber with sulphur and is a key method in the manufacturing of rubber products.

Step 3: Reviewing the Options

We review each of the options provided: (a) annealing, (b) vulcanization, (c) quenching, and (d) none of these. Annealing and quenching are processes generally associated with metals, not rubber. Therefore, the correct answer related to rubber and sulphur treatment is likely vulcanization.

Step 4: Confirming the Explanation

Vulcanization improves the elasticity and strength of rubber by forming cross-links between polymer chains through sulphur atoms. Hence, sulphur treatment of rubber is referred to as vulcanization.

Key Concepts

Rubber Treatment

Rubber treatment refers to the processes involved in improving the properties of raw rubber. Raw rubber naturally has some limitations. It can be sticky, not very durable, and over time, it loses its elasticity. That's where rubber treatment steps in to help. The most well-known method of rubber treatment is vulcanization.

This involves adding chemicals like sulphur to raw rubber. The purpose is to alter the rubber's properties to make it more useful for industrial and everyday applications. Through these treatments, the flexibility and resilience of the rubber increase, making it suitable for a wider variety of products. Existing treatments enhance the strength and durability of rubber, making it less prone to wear and environmental damage.

• This results in rubber that can withstand more stress compared to raw rubber.
• Such treatments ensure the rubber maintains its shape and properties under extreme conditions.

Sulphur Cross-linking

Sulphur cross-linking is an essential aspect of the vulcanization process. When rubber is treated with sulphur, a remarkable transformation occurs. This transformation is driven by the creation of sulphur cross-links between the long chains of natural rubber polymers.

These sulphur cross-links are instrumental in forming bridges that connect one polymer chain to another. This linkage is paramount in enhancing the rubber's toughness and elasticity. Here's how it works:

• The sulphur atoms create a network structure that binds multiple polymer chains together.
• This network greatly restricts the movement of the polymer chains, providing the rubber with enhanced mechanical strength.
• It also imparts the ability to regain its shape after stretching or compression, which is known as elasticity.

With sulphur cross-linking, rubber becomes not only stronger but also capable of withstanding a variety of environmental stresses, including temperature variations and exposure to water or oils.

Polymer Chemistry

Polymer chemistry is the scientific field that explores the structure, properties, and reactions of polymers. Polymers are large molecules comprised of repeated subunits called monomers. Rubber itself is a natural polymer, made from the monomer isoprene.

Understanding polymer chemistry is essential for improving materials like rubber. Through this chemistry, we learn how to manipulate the molecular structure of polymers to attain desired characteristics. For instance, vulcanization, a product of polymer chemistry, alters the properties of rubber by introducing cross-links with sulphur.

• This transformation increases rubber's toughness and elasticity.
• It also provides a greater lifespan and improved resistance to environmental factors.

Polymer chemistry focuses not just on the creation of polymer materials but also on their application in everyday products. This makes it foundational in the development of countless items used across different industries, from automotive to fashion to technology.