The reactive species in the nitration of benzene is

Options

A. `NO_(3)`
B. `NHO_(3)`
C. `NO_(2)^(+)`
D. `NO_(2)^(-)`

Answer

To determine the reactive species in the nitration of benzene, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nitration Reaction**:
- Nitration of benzene involves the introduction of a nitro group (NO2) into the benzene ring. This reaction typically occurs in the presence of concentrated nitric acid (HNO3) and sulfuric acid (H2SO4).

2. **Formation of the Electrophile**:
- The first step in the nitration process is the generation of the electrophile. In this case, the electrophile is the nitronium ion (NO2+).
- The nitric acid reacts with sulfuric acid to produce the nitronium ion. The reaction can be summarized as follows:
\[ \text{HNO}_3 + \text{H}_2\text{SO}_4 \rightarrow \text{NO}_2^+ + \text{HSO}_4^- + \text{H}_2\text{O} \]

3. **Identifying the Reactive Species**:
- The nitronium ion (NO2+) is the active electrophile that will react with the benzene ring. This ion is positively charged and is highly reactive, making it the key species in the nitration reaction.

4. **Reaction with Benzene**:
- The benzene ring, which contains delocalized π electrons, will react with the nitronium ion. The electrophile attacks the benzene ring, leading to the formation of a sigma complex (also known as an arenium ion).
- This step involves the breaking of one of the π bonds in the benzene ring and the formation of a new bond between the benzene and the nitronium ion.

5. **Final Product Formation**:
- After the formation of the sigma complex, a proton (H+) is lost from the ring, restoring the aromaticity of benzene and resulting in the formation of nitrobenzene (C6H5NO2) as the final product.

### Conclusion:
The reactive species in the nitration of benzene is the nitronium ion (NO2+).