Among the following , the compound that undergoes nitration readily is

Options

A. Benzoic acid
B. Toluene
C. Phenol
D. Nitrobenzene

Explanation

To determine which compound undergoes nitration readily among the given options (benzoic acid, toluene, phenol, and nitrobenzene), we need to analyze the electron density on the benzene ring of each compound. Nitration is an electrophilic substitution reaction, and the rate of this reaction depends on the electron density of the aromatic ring.

### Step-by-Step Solution:

1. **Understanding Nitration**:
- Nitration is an electrophilic substitution reaction where a nitro group (NO2) is introduced into an aromatic compound. The reagents used are concentrated nitric acid (HNO3) and concentrated sulfuric acid (H2SO4).

2. **Analyzing the Compounds**:
- **Benzoic Acid**: Contains a carboxylic acid group (-COOH), which is a -M (minus mesomeric) and -I (minus inductive) group. This group pulls electron density away from the benzene ring, making it less reactive towards electrophiles.

- **Toluene**: Contains a methyl group (-CH3), which is a +I (plus inductive) group. This group donates electron density to the benzene ring, enhancing its reactivity towards electrophilic substitution.

- **Phenol**: Contains a hydroxyl group (-OH), which is a +M (plus mesomeric) group. This group increases electron density on the benzene ring significantly, making phenol very reactive towards electrophiles.

- **Nitrobenzene**: Contains a nitro group (-NO2), which is a -M (minus mesomeric) and -I (minus inductive) group. This group pulls electron density away from the benzene ring, making it less reactive towards electrophiles.

3. **Comparing Reactivity**:
- Benzoic acid has reduced reactivity due to the electron-withdrawing effect of the carboxylic group.
- Toluene has increased reactivity due to the electron-donating effect of the methyl group.
- Phenol has very high reactivity due to the strong electron-donating effect of the hydroxyl group.
- Nitrobenzene has low reactivity due to the strong electron-withdrawing effect of the nitro group.

4. **Conclusion**:
- Among the compounds analyzed, **phenol** has the highest electron density on the benzene ring, making it the compound that undergoes nitration most readily.

### Final Answer:
**Phenol is the compound that undergoes nitration readily.**