Choose the correct option from the following :

Options

A. In the electrophilic substitution of toluene with `Br_2`,iron (III) bromide acts as a Lewis acid.
B. In the reaction of toluene with `Cl_2//FeCl_3`, ortho and para isomers are easily separated.
C. Similar reaction with iodine is reversible in nature.
D. All of these.

Explanation

To solve the question, we need to analyze each of the options provided in the context of electrophilic substitution reactions involving toluene and halogens.

### Step-by-Step Solution:

1. **Understanding Electrophilic Substitution in Toluene:**
- Toluene (C6H5CH3) undergoes electrophilic substitution reactions where the hydrogen atom on the aromatic ring is replaced by an electrophile. In this case, we are considering bromine (Br2) in the presence of a Lewis acid catalyst like FeBr3.

2. **Analyzing the First Option:**
- The reaction of toluene with bromine in the presence of FeBr3 leads to the formation of brominated products. The major products are ortho and para bromotoluene. The para product is usually favored due to steric hindrance in the ortho position.
- **Conclusion:** The first option is correct.

3. **Analyzing the Second Option:**
- When toluene reacts with chlorine (Cl2) in the presence of a catalyst, it also forms ortho and para isomers. The melting points of these isomers differ significantly, which allows for their separation through crystallization or other methods.
- **Conclusion:** The second option is correct.

4. **Analyzing the Third Option:**
- The reaction of toluene with iodine (I2) is indeed reversible. Iodine is a larger atom and does not react as vigorously as bromine or chlorine, leading to a reversible reaction.
- **Conclusion:** The third option is correct.

5. **Analyzing the Fourth Option:**
- Since all three previous options are correct, the fourth option stating "all of these" is also correct.
- **Conclusion:** The fourth option is correct.

### Final Answer:
All of the options provided are correct. Therefore, the answer is **"All of these."**