Assertion : The physical properties of natural rubber can be improved by vulcanisation .
Reason : Neoprene is the monomer of natural rubber .

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion .
B. If both assertion and reason are true but reason is not the correct explanation of assertion .
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

To solve the assertion-reason question, we will analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states: "The physical properties of natural rubber can be improved by vulcanization."

- **Vulcanization** is a chemical process that involves heating natural rubber with sulfur. This process creates cross-links between the polymer chains, which enhances the physical properties of rubber, such as increasing its tensile strength, elasticity, and resistance to solvents.

### Step 2: Evaluate the Assertion
- Since vulcanization indeed improves the physical properties of natural rubber, we can conclude that the assertion is **correct**.

### Step 3: Understand the Reason
The reason states: "Neoprene is the monomer of natural rubber."

- **Neoprene** is not the monomer of natural rubber. The actual monomer of natural rubber is **isoprene** (or 2-methyl-1,3-butadiene). Neoprene is a synthetic rubber that is made from the polymerization of chloroprene, which is a different compound.

### Step 4: Evaluate the Reason
- Since neoprene is not the monomer of natural rubber, the reason is **incorrect**.

### Conclusion
- The assertion is true, while the reason is false. Therefore, the correct answer is that the assertion is true and the reason is false.

### Final Answer
- Assertion: True
- Reason: False

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