On hydrolysis `CaC_(2)` gives a gas which on trimerisation gives

Options

A. `C_(2)H_(2)`
B. `C_(6)H_(6)`
C. `C_(2)H_(4)`
D. `C_(3)H_(8)`

Answer

To solve the question step by step, we will break down the process of hydrolysis of calcium carbide and the subsequent trimerization of the gas produced.

### Step 1: Hydrolysis of Calcium Carbide
Calcium carbide (CaC₂) reacts with water (H₂O) during hydrolysis. The reaction can be written as follows:

\[ \text{CaC}_2 + 2 \text{H}_2\text{O} \rightarrow \text{C}_2\text{H}_2 + \text{Ca(OH)}_2 \]

In this reaction, calcium carbide reacts with water to produce acetylene (C₂H₂) gas and calcium hydroxide (Ca(OH)₂).

### Step 2: Identify the Gas Produced
From the hydrolysis reaction, we can see that the gas produced is acetylene (C₂H₂).

### Step 3: Trimerization of Acetylene
Trimerization refers to the reaction where three molecules of a compound combine to form a larger compound. In this case, three molecules of acetylene (C₂H₂) will combine. The reaction can be represented as:

\[ 3 \text{C}_2\text{H}_2 \rightarrow \text{C}_6\text{H}_6 \]

### Step 4: Structure of the Product
The trimerization of acetylene results in the formation of benzene (C₆H₆). The structure of benzene is a cyclic compound with alternating double bonds, which can be represented as:

```
H H
\ /
C = C
/ \
H H
| |
C C
/ \
H H
```

### Conclusion
Thus, the final product obtained from the trimerization of acetylene is benzene (C₆H₆).

### Final Answer
The gas produced on hydrolysis of calcium carbide, which on trimerization gives benzene, is:

**C₆H₆ (Benzene)**

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