Which is most reactive towards `Br_(2)` in the prsence of `FeBr_(3)`?

Options

A. Anisole
B. Benzene
C. Bromolbenzene
D. Nitrobenzene

Explanation

To determine which compound is most reactive towards bromine (Br₂) in the presence of FeBr₃, we need to analyze the electronic effects of the substituents on each compound. The compounds in question are anisole, benzene, bromobenzene, and nitrobenzene.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- Anisole (C₆H₅OCH₃)
- Benzene (C₆H₆)
- Bromobenzene (C₆H₅Br)
- Nitrobenzene (C₆H₅NO₂)

2. **Understand the Reaction**:
- The reaction involves electrophilic substitution where Br₂ in the presence of FeBr₃ generates a bromine electrophile (Br⁺). This electrophile seeks electron-rich sites on the aromatic ring for substitution.

3. **Evaluate the Substituents**:
- **Anisole**: Contains an OCH₃ (methoxy) group, which is an electron-donating group (+M effect). This increases the electron density on the benzene ring, making it more reactive towards electrophiles.
- **Benzene**: Has no substituents that significantly affect electron density. It will react at a normal rate.
- **Bromobenzene**: Contains a Br substituent. While Br can exhibit a +M effect, it also has a -I (inductive) effect which is stronger, making it an electron-withdrawing group. This decreases the reactivity towards electrophiles.
- **Nitrobenzene**: Contains a NO₂ group, which is a strong electron-withdrawing group. This significantly decreases the electron density on the benzene ring, making it the least reactive towards electrophiles.

4. **Rank the Reactivity**:
- Anisole (most reactive due to +M effect)
- Benzene (normal reactivity)
- Bromobenzene (less reactive due to -I effect)
- Nitrobenzene (least reactive due to strong -I effect)

5. **Conclusion**:
- The compound that is most reactive towards Br₂ in the presence of FeBr₃ is **Anisole**.

### Final Answer:
**Anisole** is the most reactive towards Br₂ in the presence of FeBr₃.