………..on hydrolysis gives ethyne while …………..on hydrolysis gives methane.

Answer

To solve the question, we need to identify which compounds, when hydrolyzed, produce ethyne and methane respectively.

### Step-by-Step Solution:

1. **Understanding Hydrolysis**:
Hydrolysis is a chemical reaction involving water that breaks down compounds. In this case, we are looking for specific compounds that yield ethyne (C2H2) and methane (CH4) upon hydrolysis.

**Hint**: Remember that hydrolysis involves the reaction of a compound with water.

2. **Identifying Ethyne Production**:
Ethyne can be produced from calcium carbide (CaC2). The reaction is as follows:
\[ \text{CaC}_2 + 2 \text{H}_2\text{O} \rightarrow \text{C}_2\text{H}_2 + \text{Ca(OH)}_2 \]
Here, calcium carbide reacts with water to produce ethyne and calcium hydroxide.

**Hint**: Look for compounds that are known to produce ethyne when they react with water.

3. **Identifying Methane Production**:
Methane can be produced from aluminum carbide (Al4C3). The reaction is:
\[ \text{Al}_4\text{C}_3 + 12 \text{H}_2\text{O} \rightarrow 4 \text{Al(OH)}_3 + 3 \text{CH}_4 \]
In this reaction, aluminum carbide reacts with water to yield methane and aluminum hydroxide.

**Hint**: Consider compounds that yield methane when hydrolyzed.

4. **Final Answers**:
- Calcium carbide on hydrolysis gives ethyne.
- Aluminum carbide on hydrolysis gives methane.

Therefore, the completed sentence is: "Calcium carbide on hydrolysis gives ethyne while aluminum carbide on hydrolysis gives methane."

### Summary of Answers:
- **First Blank**: Calcium carbide
- **Second Blank**: Aluminum carbide