Which of the following compounds is a weaker acid as compared to benzoic acid?

Options

A.
B.
C.
D.

Explanation

To determine which compound is a weaker acid compared to benzoic acid, we need to analyze the effects of substituents on the benzoic acid structure.

### Step-by-Step Solution:

1. **Understanding Benzoic Acid**:
- Benzoic acid (C6H5COOH) is a carboxylic acid where a carboxyl group (-COOH) is attached to a benzene ring. Its acidic strength is influenced by the substituents on the benzene ring.

2. **Identifying the Effects of Substituents**:
- Substituents can either be electron-withdrawing groups (EWGs) or electron-donating groups (EDGs).
- EWGs increase the acidity of carboxylic acids by stabilizing the negative charge on the conjugate base (the carboxylate ion).
- EDGs decrease the acidity by destabilizing the negative charge on the conjugate base.

3. **Analyzing the Options**:
- **Option A**: Contains a chlorine substituent (Cl), which is an EWG. This would increase the acidity, making it stronger than benzoic acid.
- **Option B**: Contains a nitro group (NO2), which is also an EWG. This would also increase the acidity, making it stronger than benzoic acid.
- **Option C**: Contains a methyl group (CH3), which is an EDG. This would decrease the acidity, making it weaker than benzoic acid.
- **Option D**: Contains a sulfonic acid group (SO3H), which is an EWG. This would increase the acidity, making it stronger than benzoic acid.

4. **Conclusion**:
- Among the given options, the compound with the methyl group (Option C) is a weaker acid compared to benzoic acid.

### Final Answer:
**Option C (with CH3 group) is a weaker acid compared to benzoic acid.**