Assertion: Stannous chloride is a powerful oxidising agent which oxidises mercuric chloride to mercury
Reason: Stannous chloride gives grey precipitate with mercuric chloride, but stannic chloride does not do so.

Options

A. Statement-1 is True, Statement-2 is True and Statement-2 is a correct explanation for Statement-1.
B. Statement-1 is True, Statement-2 is True and Statement-2 is NOT a correct explanation for Statement-1.
C. Statement-1 is True, Statement-2 is False.
D. Statement-1 is False, Statement-2 is True.

Explanation

To solve the assertion-reason question, we need to analyze both the assertion and the reason provided.

### Step 1: Analyze the Assertion
**Assertion:** Stannous chloride (SnCl2) is a powerful oxidizing agent that oxidizes mercuric chloride (HgCl2) to mercury (Hg).

- **Understanding Stannous Chloride:** Stannous chloride (SnCl2) is known to act as a reducing agent rather than an oxidizing agent. It can reduce other substances while being oxidized itself.
- **Reaction with Mercuric Chloride:** When SnCl2 reacts with HgCl2, it does not oxidize HgCl2 to elemental mercury (Hg). Instead, it reduces Hg from +2 oxidation state in HgCl2 to 0 oxidation state in elemental mercury (Hg).

**Conclusion for Assertion:** The assertion is incorrect because stannous chloride is not a powerful oxidizing agent; it acts as a reducing agent.

### Step 2: Analyze the Reason
**Reason:** Stannous chloride gives a gray precipitate with mercuric chloride, but stannic chloride (SnCl4) does not do so.

- **Formation of Precipitate:** When SnCl2 reacts with HgCl2, it forms a gray precipitate of mercurous chloride (Hg2Cl2). This gray precipitate is indicative of the reaction between stannous chloride and mercuric chloride.
- **Stannic Chloride:** Stannic chloride (SnCl4) does not form this gray precipitate because it does not react with HgCl2 in the same way as SnCl2.

**Conclusion for Reason:** The reason is correct because it accurately describes the formation of a gray precipitate when stannous chloride reacts with mercuric chloride.

### Final Conclusion
- **Assertion:** Incorrect
- **Reason:** Correct

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