Which of the following compound liberates acidic gas during its hydrolysis?

Options

A. `Ca_(3)P_(2)`
B. `AlN`
C. `Al_(2)S_(3)`
D. `CaH_(2)`

Explanation

To determine which compound liberates an acidic gas during hydrolysis, we need to analyze the hydrolysis reactions of the given compounds: Ca3P2, AlN, Al2S3, and CaH2.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds given are:
- Ca3P2 (Calcium Phosphide)
- AlN (Aluminum Nitride)
- Al2S3 (Aluminum Sulfide)
- CaH2 (Calcium Hydride)

2. **Analyze Hydrolysis of Each Compound**:
- **Ca3P2**: When calcium phosphide is hydrolyzed, it reacts with water to produce calcium hydroxide and phosphine (PH3), which is a basic gas.
\[ \text{Ca}_3\text{P}_2 + 6\text{H}_2\text{O} \rightarrow 3\text{Ca(OH)}_2 + 2\text{PH}_3 \]
PH3 is not acidic.

- **AlN**: Hydrolysis of aluminum nitride produces aluminum hydroxide and ammonia (NH3), which is also basic.
\[ \text{AlN} + 3\text{H}_2\text{O} \rightarrow \text{Al(OH)}_3 + \text{NH}_3 \]
NH3 is not acidic.

- **Al2S3**: Hydrolysis of aluminum sulfide yields aluminum hydroxide and hydrogen sulfide (H2S), which is an acidic gas.
\[ \text{Al}_2\text{S}_3 + 6\text{H}_2\text{O} \rightarrow 2\text{Al(OH)}_3 + 3\text{H}_2\text{S} \]
H2S is acidic.

- **CaH2**: Hydrolysis of calcium hydride produces calcium hydroxide and hydrogen gas (H2), which is neutral.
\[ \text{CaH}_2 + 2\text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + \text{H}_2 \]
H2 is neutral.

3. **Conclusion**: Based on the hydrolysis reactions analyzed, the compound that liberates an acidic gas during hydrolysis is **Al2S3**, which produces hydrogen sulfide (H2S).

### Final Answer:
The compound that liberates an acidic gas during its hydrolysis is **Al2S3**.

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