Assertion : The pressure of a gas is inversely proportional to its volume at constant temperature and n.
Reason : The gas volume is directly proportional to n at constant temperature and pressure .

Options

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

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the pressure of a gas is inversely proportional to its volume at constant temperature and number of moles (n).
- This relationship is described by Boyle's Law, which states that for a given amount of gas at constant temperature, the pressure (P) multiplied by the volume (V) is a constant (PV = k). Therefore, if the volume increases, the pressure decreases, and vice versa.
- Thus, the assertion is **true**.

2. **Understanding the Reason**:
- The reason states that the gas volume is directly proportional to the number of moles (n) at constant temperature and pressure.
- This relationship is described by Avogadro's Law, which states that at constant temperature and pressure, the volume of a gas is directly proportional to the number of moles of the gas (V ∝ n).
- Therefore, if the number of moles increases, the volume increases as well. Thus, the reason is also **true**.

3. **Analyzing the Relationship**:
- While both the assertion and reason are true, the reason does not correctly explain the assertion. The assertion is about the relationship between pressure and volume, while the reason discusses the relationship between volume and the number of moles.
- Therefore, while both statements are correct, the reason does not provide a correct explanation for the assertion.

4. **Conclusion**:
- The correct answer is that both the assertion and reason are true, but the reason is not a correct explanation of the assertion.

### Final Answer:
- **Both the assertion and reason are true, but the reason is not a correct explanation of the assertion.**