The nitrosation of N, N-dimethylaniline takes place through the attack of electrophile

Options

A. nitronium ion
B. protonated nitrous acid
C. nitrous acid
D. nitrosonium ion

Answer

To solve the question regarding the nitrosation of N,N-dimethylaniline, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactant**:
- The reactant is N,N-dimethylaniline, which has the structure:
\[ \text{C}_6\text{H}_4(\text{N(CH}_3\text{)}_2) \]
- This compound has a nitrogen atom (from the amine) bonded to two methyl groups.

2. **Determine the Nature of the Reaction**:
- Nitrosation involves the introduction of a nitroso group (–NO) into the organic compound. In this case, we are looking for the electrophile that will react with N,N-dimethylaniline.

3. **Identify the Electrophile**:
- The electrophile in nitrosation is the nitrosonium ion (NO⁺). This ion is generated from nitrous acid (HNO₂) when treated with a strong acid (like HCl).
- The reaction can be summarized as:
\[ \text{NaNO}_2 + \text{HCl} \rightarrow \text{NO}^+ + \text{NaCl} + \text{H}_2\text{O} \]

4. **Mechanism of the Reaction**:
- The N,N-dimethylaniline acts as a nucleophile and attacks the nitrosonium ion (NO⁺).
- The nitrosonium ion will preferentially add to the para position of the aromatic ring due to steric hindrance at the ortho position.

5. **Final Product Formation**:
- The product formed will be a nitroso derivative of N,N-dimethylaniline, specifically 4-nitroso-N,N-dimethylaniline:
\[ \text{C}_6\text{H}_4(\text{N(CH}_3\text{)}_2)(\text{NO}) \]

6. **Conclusion**:
- The correct electrophile for the nitrosation of N,N-dimethylaniline is the nitrosonium ion (NO⁺), making option D the correct answer.