Assertion (A): In aqueous solution, `SO_(2)` reacts with `H_(2)S` liberating sulphur
Reason (R ): `SO_(2)` is an effective reducing agent.

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)` and `(R )` are incorrect.

Explanation

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided in the question.

### Step 1: Analyze the Assertion (A)
The assertion states that in aqueous solution, `SO2` reacts with `H2S` liberating sulfur.

**Reaction:**
The reaction can be represented as:
\[ \text{SO}_2 + 2 \text{H}_2\text{S} \rightarrow \text{S} + 2 \text{H}_2\text{O} \]

This reaction indicates that sulfur dioxide (`SO2`) reacts with hydrogen sulfide (`H2S`) to produce sulfur and water. Therefore, the assertion is **correct**.

### Step 2: Analyze the Reason (R)
The reason states that `SO2` is an effective reducing agent.

To determine if this is true, we need to understand the behavior of `SO2` in redox reactions.

1. In the reaction above, `H2S` is oxidized to sulfur, meaning it loses electrons. Therefore, `H2S` acts as the reducing agent.
2. On the other hand, `SO2` is reduced to sulfur, meaning it gains electrons. This indicates that `SO2` acts as an oxidizing agent, not a reducing agent.

Thus, the reason is **incorrect**.

### Conclusion
- The assertion (A) is correct: `SO2` does react with `H2S` to liberate sulfur.
- The reason (R) is incorrect: `SO2` is not an effective reducing agent; it is actually an oxidizing agent.

### Final Answer
Both Assertion (A) is correct, but Reason (R) is incorrect. Therefore, the correct option is **C**.

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