The reaction -
`CH_(3)COCl + H_(2) underset(Pd//BaSO_(4))overset("Xylene")(rarr) CH_(3)CHO + HCl` is

Options

A. Stephen’s reaction
B. Rosenmund reaction
C. Hoffmann reaction
D. Cannizzaro’s reaction

Answer

To solve the question regarding the reaction of CH₃COCl with H₂ in the presence of Pd/BaSO₄ and Xylene, we need to identify the type of reaction that is taking place.

### Step-by-Step Solution:

1. **Identify the Reactants and Products**:
- The reactants are CH₃COCl (acetyl chloride) and H₂ (hydrogen gas).
- The product is CH₃CHO (acetaldehyde) and HCl (hydrochloric acid).

2. **Recognize the Role of the Catalyst**:
- The catalyst used is Palladium (Pd) in the presence of BaSO₄ (barium sulfate) and Xylene.
- This combination is known as the Rosenmund catalyst, which is specifically used for the reduction of acyl chlorides to aldehydes.

3. **Understanding the Reaction Mechanism**:
- In this reaction, the acyl chloride (CH₃COCl) undergoes reduction by hydrogen gas (H₂) in the presence of the catalyst.
- The Pd/BaSO₄ catalyst facilitates the addition of hydrogen across the carbonyl group of the acyl chloride, leading to the formation of the aldehyde (CH₃CHO).

4. **Identify the Type of Reaction**:
- Since we are converting an acyl chloride to an aldehyde using hydrogen gas and a specific catalyst, this reaction is classified as a Rosenmund reduction.

5. **Conclusion**:
- Therefore, the reaction `CH₃COCl + H₂ (Pd/BaSO₄, Xylene) → CH₃CHO + HCl` is a Rosenmund reduction.

### Final Answer:
The reaction is a **Rosenmund reduction**.