The electrophile that participates in nitration of benzene is

Options

A. `NO^+`
B. `NO_2^+`
C. NO
D. `NO_3^-`

Answer

To determine the electrophile that participates in the nitration of benzene, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reaction Conditions**:
- The nitration of benzene involves the use of concentrated nitric acid (HNO3) and concentrated sulfuric acid (H2SO4).

2. **Understand the Role of Acids**:
- Concentrated sulfuric acid acts as a catalyst and helps in generating the electrophile from nitric acid.

3. **Formation of the Electrophile**:
- When concentrated HNO3 and H2SO4 are mixed, they react to form the nitronium ion (NO2+), which is the electrophile responsible for the nitration process.

4. **Electrophilic Attack on Benzene**:
- The nitronium ion (NO2+) then attacks the benzene ring. Benzene, being an aromatic compound, has a high electron density due to its π-electron cloud, making it susceptible to electrophilic attack.

5. **Formation of Nitrobenzene**:
- Upon the attack of the nitronium ion, one of the hydrogen atoms on the benzene ring is replaced by a nitro group (NO2), resulting in the formation of nitrobenzene.

6. **Conclusion**:
- Therefore, the electrophile that participates in the nitration of benzene is the nitronium ion (NO2+).

### Final Answer:
The electrophile that participates in the nitration of benzene is **NO2+**.

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