Assertion (A): When hydrogen gas at high pressure and room temperature expands adiabatically into a region of low pressure, there is a decrease in temperature.
Reason (R ) : Hydrogen gas at room temperature is above its inversion temperature.

Options

A. If both (A) and (R ) are correct, and (R ) is the correct explanation for (A).
B. If the both (A) and (R ) are correct, but(R ) is not a correct explanation for (A).
C. If (A) is correct, but (R ) is incorrect.
D. If (A) is incorrect, but (R ) is correct.

Explanation

To solve the assertion and reason question, we will analyze both the assertion (A) and the reason (R) step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that when hydrogen gas at high pressure and room temperature expands adiabatically into a region of low pressure, there is a decrease in temperature.
- In an adiabatic process, there is no heat exchange with the surroundings. For an ideal gas, when it expands adiabatically, it does work on the surroundings, which typically leads to a decrease in temperature.

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