Assertion : For a certain amount of gas, at constant temperature the product `pV` is always constant.
Reason : This is statement of Charle's law.

Options

A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.

Explanation

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

### Step 1: Understand the Assertion
The assertion states that for a certain amount of gas at constant temperature, the product \( pV \) (pressure multiplied by volume) is always constant. This is indeed a correct statement. According to the ideal gas law, \( PV = nRT \), where:
- \( P \) = pressure
- \( V \) = volume
- \( n \) = number of moles
- \( R \) = universal gas constant
- \( T \) = temperature

If the amount of gas (n) and the temperature (T) are constant, then \( PV \) must also be constant.

### Step 2: Understand the Reason
The reason states that this is a statement of Charles' law. However, this is incorrect. Charles' law states that at constant pressure, the volume of a gas is directly proportional to its temperature (i.e., \( V/T = \text{constant} \)). The statement regarding the product \( PV \) being constant at constant temperature refers to Boyle's law, which states that for a fixed amount of gas at constant temperature, the product of pressure and volume is constant.

### Step 3: Conclusion
- The assertion is correct.
- The reason is incorrect.

Thus, the correct answer is that the assertion is true, but the reason is false.

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