Aniline dissolved in dilute HCL is reacted with sodium nitrate at `0^(@)C` . This solution was added dropwise to a solution containing equimolar mixture of aniline and phenol in dil. HCl. The structure of the major product is :

Options

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B.
C.
D.

Explanation

To solve the problem, we need to follow the steps of the reaction involving aniline, sodium nitrite, and the subsequent reaction with phenol in dilute HCl.

### Step-by-Step Solution:

1. **Identify the Reactants**:
- Aniline (C6H5NH2) is dissolved in dilute HCl.
- Sodium nitrite (NaNO2) is added to this solution at 0°C.

2. **Diazotization Reaction**:
- Aniline reacts with sodium nitrite in the presence of dilute HCl to form a diazonium salt. The reaction can be represented as:
\[ \text{C6H5NH2} + \text{NaNO2} + \text{HCl} \rightarrow \text{C6H5N2}^+ \text{Cl}^- + \text{NaCl} + \text{H2O} \]
- The product formed is benzenediazonium chloride (C6H5N2Cl).

3. **Preparation of the Second Solution**:
- A solution containing an equimolar mixture of aniline (C6H5NH2) and phenol (C6H5OH) in dilute HCl is prepared.

4. **Addition of Diazotized Solution**:
- The diazonium salt solution is added dropwise to the mixture of aniline and phenol in dilute HCl.

5. **Electrophilic Attack**:
- The diazonium salt (C6H5N2^+) is electron deficient and can undergo electrophilic substitution.
- Between aniline and phenol, aniline is more nucleophilic because it has a lone pair of electrons on the nitrogen atom that can stabilize the positive charge of the diazonium salt.

6. **Formation of the Product**:
- Aniline will attack the diazonium salt, leading to the formation of a new compound. The reaction can be represented as:
\[ \text{C6H5N2}^+ + \text{C6H5NH2} \rightarrow \text{C6H5N(H)C6H4N2}^+ \]
- This results in the formation of a product where aniline is bonded to the diazonium nitrogen, forming an azo compound.

7. **Final Structure**:
- The major product formed is an azo compound where the aniline is directly attached to the diazonium salt, resulting in the structure:
\[ \text{C6H5-N=N-C6H4-NH2} \]

### Conclusion:
The major product of the reaction is an azo compound formed from the reaction of the diazonium salt with aniline.