Which of the following would give benzene when reacted with `PhMgBr` ?

Options

A.
B. `H_(2)`
C. Methyl amine
D. `NH_(3)`

Explanation

To determine which of the given compounds would yield benzene when reacted with phenyl magnesium bromide (PhMgBr), we can analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding the Reaction**:
- Phenyl magnesium bromide (PhMgBr) is a Grignard reagent. It reacts with compounds containing active hydrogen (like -OH, -NH, or -SH groups) to form a corresponding magnesium salt and release benzene.

2. **Option A: Phenol (C6H5OH)**:
- When phenol reacts with PhMgBr, the -OH group will react with the Grignard reagent. The oxygen will take the magnesium bromide part, and the hydrogen from the -OH will combine with the phenyl group to form benzene.
- **Reaction**:
\[ C_6H_5OH + PhMgBr \rightarrow C_6H_5O^-MgBr^+ + HPh \rightarrow C_6H_6 + MgBrOH \]
- **Conclusion**: Produces benzene.

3. **Option B: Ethanol (C2H5OH)**:
- Ethanol also contains an -OH group. Similar to phenol, the -OH will react with PhMgBr, leading to the formation of benzene.
- **Reaction**:
\[ C_2H_5OH + PhMgBr \rightarrow C_2H_5O^-MgBr^+ + HPh \rightarrow C_6H_6 + MgBrOEt \]
- **Conclusion**: Produces benzene.

4. **Option C: Methylamine (CH3NH2)**:
- Methylamine contains an -NH2 group, which is also an active hydrogen. The nitrogen will bond with the magnesium bromide, and the hydrogen will combine with the phenyl group to yield benzene.
- **Reaction**:
\[ CH_3NH_2 + PhMgBr \rightarrow CH_3N^-MgBr^+ + HPh \rightarrow C_6H_6 + MgBrNHCH_3 \]
- **Conclusion**: Produces benzene.

5. **Option D: Ammonia (NH3)**:
- Ammonia has an active hydrogen as well. The -NH2 group will react with PhMgBr, leading to the formation of benzene.
- **Reaction**:
\[ NH_3 + PhMgBr \rightarrow NH_2^-MgBr^+ + HPh \rightarrow C_6H_6 + MgBrNH_2 \]
- **Conclusion**: Produces benzene.

### Final Conclusion:
All options (A, B, C, and D) will produce benzene when reacted with phenyl magnesium bromide.