Which statements are correct ?

Options

A. Phenol and aniline give coupling reaction with diazonium salt.
B. Phenol couples with diazonium salt in mild basic conditions `(pH = 8-10)`.
C. Aniline couples with diazonium salt in mild acidic condition `(pH = 4-6)`.
D. Both phenol and aniline couple with diazonium salt in neutral condition `(pH = 7)`.

Answer

To determine which statements are correct regarding the coupling reactions of phenol and aniline with diazonium salts, we can break down the process step by step:

### Step 1: Understand the Reactants
- **Aniline**: Aniline is an aromatic amine with the formula C6H5NH2. It has a benzene ring attached to an amino group (-NH2).
- **Phenol**: Phenol is an aromatic compound with the formula C6H5OH. It consists of a benzene ring attached to a hydroxyl group (-OH).
- **Diazonium Salts**: These are compounds that contain a diazonium group (-N≡N+), typically represented as benzene diazonium chloride (C6H5N2Cl).

### Step 2: Identify the Reaction Conditions
- **For Aniline**: The coupling reaction of aniline with diazonium salts occurs in a mildly acidic medium, typically with a pH around 4 to 6.
- **For Phenol**: The coupling reaction of phenol with diazonium salts occurs in a mildly alkaline medium, with a pH around 8 to 10.

### Step 3: Write the Products of the Reactions
- **Aniline with Diazonium Salt**: When aniline reacts with benzene diazonium chloride, it forms para-aminoazobenzene.
- **Phenol with Diazonium Salt**: When phenol reacts with benzene diazonium chloride, it forms para-hydroxyazobenzene.

### Step 4: Analyze the Statements
1. **Statement A**: "Phenol and aniline give coupling reaction with diazonium salts."
- This statement is correct.

2. **Statement B**: "Phenol couples with diazonium salt in mild basic condition."
- This statement is also correct.

3. **Statement C**: "Aniline couples with diazonium salt in mild acidic condition."
- This statement is correct as well.

4. **Statement D**: "The coupling reaction occurs under neutral conditions."
- This statement is incorrect, as the reactions occur under either mildly acidic or mildly alkaline conditions.

### Conclusion
Based on the analysis, the correct statements are A, B, and C. The incorrect statement is D.

### Final Answer
The correct statements are A, B, and C.

---