Identify the correct of reactivity in electrophilic substitution reaction of the following compounds.
(1) Benzene
(2) Toluene
(3) Chlorobenzene,
(4) Nitrobenzene.

Options

A. `(1) gt (2) gt (3) gt (4)`
B. `(4) gt (3) gt (2) gt (1)`
C. `(2) gt (1) gt (3) gt (4)`
D. `(2) gt (3) gt (1) gt (4)`

Explanation

To determine the correct order of reactivity in electrophilic substitution reactions for the given compounds: benzene, toluene, chlorobenzene, and nitrobenzene, we need to analyze the effects of substituents on the benzene ring.

### Step-by-Step Solution:

1. **Understanding Electrophilic Substitution:**
- Electrophilic substitution reactions involve an electrophile attacking the benzene ring, resulting in the substitution of a hydrogen atom. The reactivity of the benzene ring in these reactions is influenced by the nature of substituents attached to it.

2. **Analyzing Benzene:**
- Benzene (C6H6) has no substituents. It is a symmetrical compound and has a moderate reactivity towards electrophilic substitution.

3. **Analyzing Toluene:**
- Toluene (C6H5CH3) has a methyl group (–CH3) attached to the benzene ring. The methyl group is an electron-donating group due to its +I (inductive) effect and hyperconjugation. This increases the electron density on the benzene ring, making it more reactive towards electrophilic substitution compared to benzene.

4. **Analyzing Chlorobenzene:**
- Chlorobenzene (C6H5Cl) has a chlorine atom attached to the benzene ring. Chlorine exhibits a –I (inductive) effect, which withdraws electron density from the ring, decreasing its reactivity. However, chlorine also has a +R (resonance) effect, which can stabilize the ring and direct substitution to the ortho and para positions. Overall, the –I effect makes chlorobenzene less reactive than toluene but more reactive than nitrobenzene.

5. **Analyzing Nitrobenzene:**
- Nitrobenzene (C6H5NO2) has a nitro group (–NO2) attached to the benzene ring. The nitro group is a strong –I (inductive) and –R (resonance) withdrawing group, which significantly decreases the electron density on the benzene ring. This makes nitrobenzene the least reactive towards electrophilic substitution.

6. **Establishing the Order of Reactivity:**
- Based on the analysis:
- Toluene (most reactive) > Benzene > Chlorobenzene > Nitrobenzene (least reactive).
- Therefore, the correct order of reactivity in electrophilic substitution reactions is:
- **Toluene > Benzene > Chlorobenzene > Nitrobenzene.**

### Final Answer:
The correct order of reactivity in electrophilic substitution reaction is:
**Toluene > Benzene > Chlorobenzene > Nitrobenzene.**