Anhydrous mercurous chloride can be prepared by:

Options

A. the reduction of `HgCl_(2)` with `SnCl_(2)` solution
B. the reaction of `HgCl_(2)` with Hg
C. the reaction of Hg with concentrated HCl
D. None of these

Answer

To prepare anhydrous mercurous chloride (Hg2Cl2), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Compounds**: We need to prepare anhydrous mercurous chloride (Hg2Cl2). The starting compound we will use is mercuric chloride (HgCl2).

2. **Choose the Reducing Agent**: To reduce mercuric chloride (HgCl2) to mercurous chloride (Hg2Cl2), we will use mercury (Hg) as the reducing agent.

3. **Write the Reaction**: The chemical reaction for the reduction can be written as:
\[ \text{HgCl}_2 + \text{Hg} \rightarrow \text{Hg}_2\text{Cl}_2 \]
This equation shows that one mole of mercuric chloride reacts with one mole of mercury to produce one mole of mercurous chloride.

4. **Conclusion**: Therefore, the correct method to prepare anhydrous mercurous chloride is by the reaction of mercuric chloride with mercury.

### Final Answer:
Anhydrous mercurous chloride can be prepared by the reaction of HgCl2 with Hg.