Question

We can overcome the undesirable properties of natural rubber by heating natural rubber with

• A. Carbon
• B. Sulphur
• C. Phosphorus
• D. Silicon

Hint:

The process of heating rubber with sulfur is called Vulcanization.
Remembering this term and its association with sulfur is key to answering questions about improving rubber's properties.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks about the process used to improve the physical properties of natural rubber, such as its strength and elasticity.

Step 2: Key Formula or Approach:
This is a factual question about a specific industrial chemical process. The process of heating natural rubber with a cross-linking agent to improve its properties is known as vulcanization.

Step 3: Detailed Explanation:
Natural rubber is a polymer of isoprene. In its raw form, it has several undesirable properties: it is soft and sticky, has low tensile strength, becomes brittle at low temperatures, and is not very elastic.
To overcome these issues, natural rubber is heated with

Sulphur. This process, discovered by Charles Goodyear, is called

vulcanization.
During vulcanization, the sulphur atoms form cross-links (disulfide or polysulfide bridges) between the long polyisoprene chains. These cross-links tie the polymer chains together, preventing them from slipping past one another.
This modification drastically improves the rubber's properties, making it stronger, tougher, more elastic, and less susceptible to temperature changes.
Carbon (in the form of carbon black) is often added as a reinforcing filler, but Sulphur is the key vulcanizing agent.

Step 4: Final Answer:
The undesirable properties of natural rubber are overcome by heating it with Sulphur.