Mercuric chloride is converted into mercury by:

Options

A. placing copper metal in aqueous solution of `HgCl_(2)`
B. treating aqueous solution of `HgCl_(2)` with excess of stannous chloride
C. treating aqueous solution `HgCl_(2)` with `PbCl_(2)` solution
D. None of these

Answer

To convert mercuric chloride (HgCl2) into mercury (Hg), we can follow these steps:

### Step 1: Reaction with Copper
1. **Place copper metal in an aqueous solution of mercuric chloride (HgCl2)**.
- The reaction is:
\[ \text{HgCl}_2 + \text{Cu} \rightarrow 2\text{CuCl} + \text{Hg} \]
- In this step, copper reduces mercuric chloride to mercury and forms cuprous chloride (CuCl).

### Step 2: Reaction with Stannous Chloride
2. **Treat the aqueous solution of mercuric chloride with excess stannous chloride (SnCl2)**.
- The reaction is:
\[ 2\text{HgCl}_2 + \text{SnCl}_2 \rightarrow \text{Hg}_2\text{Cl}_2 + \text{SnCl}_4 \]
- Here, mercuric chloride is reduced to mercurous chloride (Hg2Cl2), while stannous chloride is oxidized to stannic chloride (SnCl4).

### Step 3: Reduction of Mercurous Chloride
3. **Reduce mercurous chloride (Hg2Cl2) to metallic mercury (Hg) using excess stannous chloride**.
- The reaction is:
\[ \text{Hg}_2\text{Cl}_2 + \text{SnCl}_2 \rightarrow 2\text{Hg} + \text{SnCl}_4 \]
- In this step, mercurous chloride is reduced to metallic mercury, which appears gray in color.

### Final Summary
- The overall process involves:
1. Reduction of HgCl2 to Hg using copper.
2. Further reduction of HgCl2 to Hg2Cl2 using stannous chloride.
3. Final reduction of Hg2Cl2 to metallic mercury using stannous chloride.

### Conclusion
The correct options for the conversion of mercuric chloride to mercury are:
- **Option A**: Reaction with copper.
- **Option B**: Reaction with excess stannous chloride.