Which of the following sulphides dissolve in dilute HCl?

Options

A. `CoS`
B. `NiS`
C. `MnS`
D. ZnS

Answer

To determine which of the given sulfides dissolve in dilute HCl, we will analyze each sulfide one by one based on their solubility in dilute hydrochloric acid.

### Step-by-Step Solution:

1. **Identify the Sulfides**: The sulfides given in the question are:
- Cobalt sulfide (CoS)
- Nickel sulfide (NiS)
- Manganese sulfide (MnS)
- Zinc sulfide (ZnS)

2. **Understand the Solubility in Dilute HCl**:
- Some sulfides are soluble in dilute acids, while others are not. We need to check each sulfide for its behavior in dilute HCl.

3. **Analyze Each Sulfide**:
- **Cobalt Sulfide (CoS)**: This sulfide is known to be insoluble in dilute HCl. It remains as a precipitate.
- **Nickel Sulfide (NiS)**: Similar to cobalt sulfide, nickel sulfide is also insoluble in dilute HCl and remains as a precipitate.
- **Manganese Sulfide (MnS)**: Manganese sulfide is soluble in dilute HCl. It will dissolve and form manganese chloride.
- **Zinc Sulfide (ZnS)**: Zinc sulfide is also soluble in dilute HCl. It dissolves to form zinc chloride.

4. **Conclusion**: Based on the analysis, the sulfides that dissolve in dilute HCl are:
- Manganese sulfide (MnS)
- Zinc sulfide (ZnS)

Thus, the correct answers are manganese sulfide and zinc sulfide.

### Final Answer:
The sulfides that dissolve in dilute HCl are:
- Manganese sulfide (MnS)
- Zinc sulfide (ZnS)