Which one of the following gives imine formation with carbonyl compounds

Options

A. `C_6H_5-NH-C_6H_5`
B. `NH_4Cl`
C. `R_3N`
D. `C_6H_5NH_2`

Answer

To determine which compound gives imine formation with carbonyl compounds, we need to understand the process of imine formation and the types of amines involved.

### Step-by-Step Solution:

1. **Understanding Imine Formation**:
- Imine formation occurs when a carbonyl compound (an aldehyde or a ketone) reacts with a primary amine (R-NH2).
- The reaction involves the nucleophilic attack of the amine on the carbonyl carbon, leading to the formation of a tetrahedral intermediate.

2. **Reaction Mechanism**:
- In the presence of a mild acidic medium, the tetrahedral intermediate loses a water molecule, resulting in the formation of a double bond between the carbon and nitrogen, thus forming an imine (C=N).

3. **Identifying the Options**:
- We need to analyze the given options to identify which one contains a primary amine:
- **Option 1**: pH-NH-pH (This is a secondary amine)
- **Option 2**: Ammonium chloride (This is not an amine; it does not contain the -NH2 group)
- **Option 3**: R3N (This is a tertiary amine)
- **Option 4**: Aniline (pH-NH2, which is a primary amine)

4. **Conclusion**:
- Among the options, only **Aniline (Option 4)** is a primary amine and can react with carbonyl compounds to form imines.

### Final Answer:
**Option 4: Aniline (pH-NH2)** gives imine formation with carbonyl compounds.

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