Which of the followiong is/are less acidic than p-nitro-phenol.

Options

A. o-Nitrophenol
B. m-Nitrophenol
C. Phenol
D. p-Cresol

Explanation

To determine which compounds are less acidic than para-nitrophenol, we will analyze the acidity of para-nitrophenol in comparison to other compounds: ortho-nitrophenol, meta-nitrophenol, phenol, and p-cresol (or chrysol).

### Step-by-Step Solution:

1. **Understanding the Structure of Para-Nitrophenol**:
- Para-nitrophenol has a hydroxyl group (-OH) attached to a benzene ring, with a nitro group (-NO2) at the para position.
- The presence of the nitro group, which is an electron-withdrawing group, increases the acidity of para-nitrophenol by stabilizing the phenoxide ion formed after deprotonation.

2. **Comparing with Ortho-Nitrophenol**:
- Ortho-nitrophenol also has a nitro group, but it is located at the ortho position.
- While it is still acidic, its acidity is less than that of para-nitrophenol due to steric hindrance and intramolecular hydrogen bonding that can occur, making it less favorable for deprotonation.

3. **Comparing with Meta-Nitrophenol**:
- Meta-nitrophenol has the nitro group at the meta position.
- The electron-withdrawing effect is less effective at the meta position compared to the para position, making meta-nitrophenol less acidic than para-nitrophenol.

4. **Comparing with Phenol**:
- Phenol itself has no electron-withdrawing groups.
- Therefore, it is less acidic than para-nitrophenol since it lacks the stabilizing effect of the nitro group.

5. **Comparing with p-Cresol (Chrysol)**:
- p-Cresol has a methyl group (-CH3) at the para position, which is an electron-donating group.
- The presence of the methyl group decreases the acidity of p-cresol compared to para-nitrophenol because electron-donating groups destabilize the negative charge on the phenoxide ion.

### Conclusion:
All the compounds being compared (ortho-nitrophenol, meta-nitrophenol, phenol, and p-cresol) are less acidic than para-nitrophenol.

### Final Answer:
- Ortho-nitrophenol, meta-nitrophenol, phenol, and p-cresol are all less acidic than para-nitrophenol.

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