When nitrobenzene is treated with `Br_(2)` in presence of `FeBr_(3)`, the major product formed is `m-`bromo`-`nitrobenzene. Statement which is related to obtain the `m-`isomer is

Options

A. The electron density at the meta position is greater than those at the ortho and para positions
B. Aromaticity is lost in the `simga-`complexes formed by the attack of `Br^(+)` at the ortho and para positions but not at the meta position.
C. The `sigma-`complex formed by the attack of `Br^(+)` at the meta position is the least destablized and the most stable among the three `sigma-`complexes
D. In the final step of regeneration of benzene ring by the loss of `H^(+)` from the `sigma-`complexes, the meta-oriented `sigma-`complex loses `H^(+)` most readily

Answer

To solve the question regarding the formation of m-bromo-nitrobenzene when nitrobenzene is treated with Br₂ in the presence of FeBr₃, we need to analyze the reaction mechanism and the influence of the nitro group on the electrophilic aromatic substitution process.

### Step-by-Step Solution:

1. **Understanding the Reactants**:
- Nitrobenzene (C₆H₄(NO₂)) contains a nitro group (-NO₂) that is a strong electron-withdrawing group due to its -M (mesomeric) effect. This means it decreases the electron density on the aromatic ring.

2. **Electrophilic Aromatic Substitution Mechanism**:
- When nitrobenzene reacts with bromine (Br₂) in the presence of a Lewis acid catalyst like FeBr₃, the bromine molecule is polarized. The FeBr₃ helps to generate a more reactive electrophile, Br⁺.

3. **Formation of the Sigma Complex**:
- The Br⁺ electrophile can attack the aromatic ring at three possible positions: ortho, meta, and para relative to the nitro group.
- Due to the electron-withdrawing nature of the nitro group, the electron density at the ortho and para positions is reduced. This makes these positions less favorable for electrophilic attack compared to the meta position.

4. **Stability of the Sigma Complex**:
- When Br⁺ attacks the meta position, the resulting sigma complex retains more electron density compared to the ortho and para complexes. This is because the positive charge generated in the ortho and para complexes is destabilized by the electron-withdrawing nitro group.

5. **Regeneration of Aromaticity**:
- After the electrophilic attack, the sigma complex loses a proton (H⁺) to regenerate the aromatic system. The loss of H⁺ from the meta position is more favorable due to the higher electron density at that position.

6. **Conclusion**:
- As a result of the above factors, the major product formed is m-bromo-nitrobenzene. The statement that relates to obtaining the m-isomer is that the electron density at the meta position is greater than that at the ortho and para positions due to the electron-withdrawing effect of the nitro group.

### Final Answer:
The major product formed is m-bromo-nitrobenzene because the electron density at the meta position is greater than at the ortho and para positions due to the electron-withdrawing effect of the nitro group.