A black sulphide is formed by the action of `H_(2)S` on

Options

A. `CaCI_(2)`
B. `CdCI_(2)`
C. `ZnCI_(2)`
D. `NaCI`

Explanation

To determine which salt forms a black sulfide when treated with hydrogen sulfide (H₂S), we will analyze the given options: calcium chloride, cadmium chloride, zinc chloride, and sodium chloride.

### Step-by-Step Solution:

1. **Identify the salts**: The salts given are:
- Calcium chloride (CaCl₂)
- Cadmium chloride (CdCl₂)
- Zinc chloride (ZnCl₂)
- Sodium chloride (NaCl)

2. **Understand the action of H₂S**: Hydrogen sulfide (H₂S) can react with certain metal ions to form metal sulfides. Some of these sulfides are colored, and we are specifically looking for a black sulfide.

3. **Analyze each salt**:
- **Calcium chloride (CaCl₂)**: When H₂S reacts with calcium ions, it forms calcium sulfide (CaS), which is typically white and not black.
- **Cadmium chloride (CdCl₂)**: When H₂S reacts with cadmium ions, it forms cadmium sulfide (CdS), which is yellow in color.
- **Zinc chloride (ZnCl₂)**: When H₂S reacts with zinc ions, it forms zinc sulfide (ZnS), which is white and not black.
- **Sodium chloride (NaCl)**: Sodium does not form a sulfide with H₂S that is colored; it remains soluble.

4. **Identify the black sulfide**: The black sulfide we are looking for is copper sulfide (CuS). However, copper chloride (CuCl₂) is not listed among the options.

5. **Conclusion**: Based on the analysis, none of the provided options will yield a black sulfide with H₂S. The black sulfide is typically associated with copper compounds, specifically copper chloride (CuCl₂), which is not included in the options.

### Final Answer:
None of the given options (calcium chloride, cadmium chloride, zinc chloride, sodium chloride) form a black sulfide when reacted with H₂S. The black sulfide is formed by copper chloride, which is not listed.