Assertion `(A)`: The process of adsorption of hydrogen on palladium is known as occlusion.
Reason `(R)` : The adsorbed hydrogen is more active than ordinary hydrogen.

Options

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

Answer

To analyze the given assertion and reason, we will break down the statements and evaluate their correctness step by step.

### Step 1: Understand the Assertion
**Assertion (A)**: The process of adsorption of hydrogen on palladium is known as occlusion.

- **Explanation**: Occlusion refers to the process where a gas (in this case, hydrogen) is absorbed into the structure of a solid (here, palladium). Palladium has a unique ability to absorb large volumes of hydrogen, forming what is known as an interstitial hydride. This means that hydrogen atoms can occupy spaces within the palladium lattice.

**Conclusion**: The assertion is correct.

### Step 2: Understand the Reason
**Reason (R)**: The adsorbed hydrogen is more active than ordinary hydrogen.

- **Explanation**: When hydrogen is adsorbed onto a metal like palladium, it can exhibit different chemical properties compared to molecular hydrogen (H₂) in the gas phase. The adsorbed hydrogen can be more reactive due to its interaction with the metal surface and the altered electronic environment.

**Conclusion**: The reason is also correct.

### Step 3: Evaluate the Relationship Between Assertion and Reason
- The assertion states that the process of adsorption is called occlusion, which is true.
- The reason states that the adsorbed hydrogen is more active than ordinary hydrogen, which is also true. However, this reason does not explain why the process is called occlusion. The term "occlusion" specifically refers to the absorption process itself, not the reactivity of the absorbed hydrogen.

### Final Conclusion
- Both the assertion and reason are correct.
- However, the reason does not serve as a correct explanation for the assertion.

### Answer Choice
Thus, the correct choice is **Option B**: Both assertion and reason are correct, but reason is not the correct explanation of A.

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