In an electrophilic substitution reaction of nitrobenzene, the presence of nitro group _________.

Options

A. deactives the ring by inductive effect.
B. activates the ring by inductive effect.
C. decreases the charge density at ortho and para position of the ring relative to meta position by resonance.
D. None of the above

Answer

To answer the question regarding the effect of the nitro group in the electrophilic substitution reaction of nitrobenzene, we can break down the explanation into several steps.

### Step-by-Step Solution:

1. **Understanding Nitrobenzene Structure**:
- Nitrobenzene consists of a benzene ring with a nitro group (NO2) attached to it. The structure can be represented as C6H5-NO2.

2. **Identifying the Nature of the Nitro Group**:
- The nitro group is an electron-withdrawing group (EWG). It pulls electron density away from the benzene ring due to its strong electronegativity.

3. **Effect of Electron Withdrawal**:
- The withdrawal of electron density by the nitro group leads to a decrease in the electron density of the benzene ring. This results in the generation of a positive charge density on the ring, particularly at the ortho and para positions relative to the nitro group.

4. **Deactivation of the Ring**:
- Because the nitro group withdraws electron density, it deactivates the benzene ring towards electrophilic substitution reactions. This means that the ring becomes less reactive to electrophiles.

5. **Resonance Considerations**:
- The nitro group can also participate in resonance, which further stabilizes the positive charge at the ortho and para positions. However, this resonance effect does not enhance the reactivity of the ring; instead, it reinforces the deactivation caused by the electron-withdrawing nature of the nitro group.

6. **Comparative Reactivity**:
- In comparison, the meta position does not experience the same degree of charge density alteration as the ortho and para positions. Therefore, the ortho and para positions are less nucleophilic compared to the meta position.

7. **Conclusion**:
- The presence of the nitro group in nitrobenzene deactivates the ring towards electrophilic substitution reactions. Thus, the correct answer is that the presence of the nitro group deactivates the ring.

### Final Answer:
The presence of the nitro group deactivates the ring in the electrophilic substitution reaction of nitrobenzene.

---