A precipitate of the following would be obtained when `HCl` is added to a solution of stannous sulphide `(SnS)` in yellow ammonium sulphide

Options

A. `SnS`
B. `SnS_2`
C. `Sn_2S_2`
D. `(NH_4)_2SnS_3`

Answer

To solve the problem, we need to analyze the reaction that occurs when hydrochloric acid (HCl) is added to a solution of stannous sulfide (SnS) in yellow ammonium sulfide.

### Step-by-Step Solution:

1. **Identify the Components**:
- The solution contains stannous sulfide (SnS) and yellow ammonium sulfide (NH₄)₂S.
- Stannous sulfide (SnS) is a compound of tin and sulfur.

2. **Understand the Reaction with HCl**:
- When HCl is added to the solution, it will react with the sulfide ions (S²⁻) present in the solution.
- The reaction can be represented as:
\[ HCl + S^{2-} \rightarrow H_2S \downarrow \]
- Hydrogen sulfide (H₂S) is a gas that has a characteristic rotten egg smell and is released as a precipitate.

3. **Consider the Stannous Ion**:
- Stannous sulfide (SnS) can also react with HCl to form stannous chloride (SnCl₂) and release sulfide ions.
- The reaction can be represented as:
\[ SnS + 2HCl \rightarrow SnCl_2 + H_2S \downarrow \]
- This confirms that H₂S is produced as a result of the reaction.

4. **Determine the Precipitate**:
- The precipitate formed in this reaction is hydrogen sulfide (H₂S), which is a gas and will escape from the solution.
- Additionally, stannous chloride (SnCl₂) is formed, which is soluble in water.

5. **Final Conclusion**:
- The precipitate obtained when HCl is added to a solution of stannous sulfide in yellow ammonium sulfide is hydrogen sulfide (H₂S).

### Summary of the Reaction:
- The addition of HCl leads to the formation of hydrogen sulfide gas as a precipitate, which is characterized by its rotten egg odor.