Which attacking species is generated from nitrating mixture during the nitration of phenol ?

Options

A. `NO_(2)^(-)`
B. `NO_(2)^(+)`
C. `NO_(2)` freeradical
D. `N_(2)O_(3)`

Answer

To determine the attacking species generated from the nitrating mixture during the nitration of phenol, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
The nitration of phenol involves a nitrating mixture, typically composed of concentrated nitric acid (HNO3) and concentrated sulfuric acid (H2SO4).

2. **Understand the Role of Sulfuric Acid**:
Sulfuric acid acts as a catalyst and helps in generating the electrophile needed for the nitration reaction. It dissociates to produce H⁺ ions and bisulfate ions (HSO4⁻).

3. **Formation of the Electrophile**:
The nitric acid (HNO3) can be represented as containing the nitronium ion (NO2⁺) when it reacts in the presence of sulfuric acid. The lone pair of electrons on the oxygen of HNO3 can interact with the H⁺ ion from sulfuric acid, leading to the formation of the nitronium ion (NO2⁺) and water (H2O).

4. **Mechanism of Electrophile Generation**:
The reaction can be summarized as follows:
- HNO3 + H2SO4 → NO2⁺ + H2O + HSO4⁻
Here, NO2⁺ is the nitronium ion, which is a strong electrophile.

5. **Nitration of Phenol**:
Phenol (C6H5OH) has a hydroxyl (OH) group that is an electron-donating group, making the benzene ring more reactive towards electrophilic substitution. The nitronium ion (NO2⁺) attacks the benzene ring at the ortho or para positions relative to the hydroxyl group.

6. **Conclusion**:
The attacking species generated from the nitrating mixture during the nitration of phenol is the nitronium ion (NO2⁺).

### Final Answer:
The attacking species generated from the nitrating mixture during the nitration of phenol is **NO2⁺** (the nitronium ion).

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