Which of the following gives ethyl benzene with phenyl methyl ketone :

Options

A. Zn–Hg+HCl
B. `LiAlH_4`
C. `KMnO_4`
D. None of the above

Answer

To solve the question, "Which of the following gives ethyl benzene with phenyl methyl ketone?", we need to analyze the options provided and understand the chemical reactions involved.

### Step-by-Step Solution:

1. **Identify the Compound**: The compound given is phenyl methyl ketone, which is also known as acetophenone. Its structure can be represented as:
\[ \text{C}_6\text{H}_5\text{C(O)CH}_3 \]
This indicates that we have a benzene ring (C6H5) attached to a carbonyl group (C=O) and a methyl group (CH3).

2. **Identify the Desired Product**: The product we want to obtain is ethyl benzene, which has the structure:
\[ \text{C}_6\text{H}_5\text{C}_2\text{H}_5 \]
This means we need to convert the carbonyl group (C=O) in acetophenone to a methylene group (CH2).

3. **Analyze the Options**:
- **Option 1: Zn/Hg + HCl**: This combination is known for the Clemmensen reduction, which reduces ketones and aldehydes to alkanes. Therefore, applying this to acetophenone would convert the carbonyl group to a methylene group, yielding ethyl benzene.
- **Option 2: Lithium Aluminium Hydride (LiAlH4)**: This reagent is a strong reducing agent that reduces ketones to alcohols, not to alkanes. Thus, it would not yield ethyl benzene.
- **Option 3: KMnO4**: This is an oxidizing agent that would oxidize compounds rather than reduce them, so it would not produce ethyl benzene.
- **Option 4: None of the above**: Since we have found a suitable option, this is not correct.

4. **Conclusion**: The only option that successfully converts phenyl methyl ketone to ethyl benzene is the first option, Zn/Hg + HCl.

### Final Answer:
The correct option is **Option 1: Zn/Hg + HCl**.