Assertion : Solids in finely divided state act as good adsorbents.
Reason : Adsorption is a surface phenomenon .

Options

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

Explanation

To solve the given assertion and reason question, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
**Assertion:** Solids in finely divided state act as good adsorbents.

- **Explanation:** This statement is true. When solids are in a finely divided state, they have a larger surface area available for adsorption. The greater the surface area, the more sites are available for molecules to adhere to the surface of the adsorbent. This is why finely divided solids are considered effective adsorbents.

### Step 2: Analyze the Reason
**Reason:** Adsorption is a surface phenomenon.

- **Explanation:** This statement is also true. Adsorption occurs at the surface of a material, where molecules from a gas or liquid adhere to the surface of a solid or liquid. This is a fundamental characteristic of adsorption, distinguishing it from absorption, where a substance is taken up throughout the bulk of a material.

### Step 3: Determine the Relationship Between Assertion and Reason
- Both the assertion and the reason are true. However, the reason provided does not fully explain why finely divided solids are good adsorbents. The correct explanation for the assertion is that finely divided solids have a high surface area, which enhances their ability to adsorb.

### Conclusion
- **Final Answer:** Both the assertion and reason are true, but the reason is not the correct explanation of the assertion. The correct explanation is that finely divided solids have a high surface area, which allows for more adsorption.