Assertion : Liquid molecules have greater potential energy at the melting point.
Reason : Intermolecular spacing between molecules increases at melting point.

Options

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

Explanation

To analyze the given assertion and reason, we can break down the concepts step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Liquid molecules have greater potential energy at the melting point."
- At the melting point, a solid transitions to a liquid. During this process, energy is absorbed, which increases the potential energy of the molecules.

2. **Understanding the Reason**:
- The reason states that "Intermolecular spacing between molecules increases at the melting point."
- When a solid melts, the molecules gain energy and move apart, which indeed increases the intermolecular spacing.

3. **Analyzing the Relationship**:
- In a solid state, molecules are closely packed and held together by strong intermolecular forces.
- As the solid melts, these forces weaken, and the molecules move further apart, leading to an increase in potential energy as work is done against these forces.

4. **Conclusion**:
- The assertion is true because the potential energy of the liquid molecules is indeed greater at the melting point due to the work done to overcome intermolecular forces.
- The reason is also true because the intermolecular spacing does increase during the melting process.
- Therefore, both the assertion and reason are true, but the reason does not explain the assertion adequately.

5. **Final Evaluation**:
- Since both statements are true, but the reason does not adequately support the assertion, the correct conclusion is that the assertion is true, and the reason is true but does not support the assertion.