In the following reaction :
`C_2H_2 underset(HgSO_4//H_2SO_4)overset(H_2O)to X hArr CH_3CHO`
What is X ?

Options

A. `CH_3CH_2OH`
B. `CH_3-O-CH_3`
C. `CH_3CH_2CHO`
D. `CH_2=CHOH`

Explanation

To solve the question, we need to analyze the reaction given:

**Reaction:**
\[ C_2H_2 \xrightarrow{HgSO_4/H_2SO_4} H_2O \rightarrow X \]

1. **Identify the Reactant:**
The reactant \( C_2H_2 \) is acetylene, which is an alkyne.

2. **Understand the Reaction Conditions:**
The presence of \( HgSO_4 \) and \( H_2SO_4 \) indicates that we are performing an acid-catalyzed hydration of the alkyne. This reaction typically leads to the formation of a carbonyl compound.

3. **Hydration of Acetylene:**
When acetylene undergoes hydration in the presence of \( HgSO_4 \) and \( H_2SO_4 \), it forms an intermediate vinyl alcohol (enol) which then tautomerizes to form a ketone or aldehyde. In this case, the product will be an aldehyde.

4. **Determine the Product:**
The reaction of acetylene with water in the presence of sulfuric acid leads to the formation of acetaldehyde (\( CH_3CHO \)). Therefore, the intermediate formed is vinyl alcohol (\( CH_2=CHOH \)), which tautomerizes to acetaldehyde.

5. **Identify X:**
Given that the final product after the reaction is \( CH_3CHO \), we conclude that \( X \) is acetaldehyde.

**Final Answer:**
\[ X = CH_3CHO \] (Acetaldehyde)

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