Which of the following is the strongest base :-

Options

A.
B.
C.
D.

Answer

To determine which of the given compounds is the strongest base, we need to analyze the acidic strength of the corresponding acids and their conjugate bases. The stronger the acid, the weaker its conjugate base, and vice versa.

### Step-by-Step Solution:

1. **Identify the Compounds**:
We have derivatives of carboxylic acids (benzoic acid derivatives) with methyl groups at different positions (ortho, meta, para).

2. **Understand Acidity and Basicity Relationship**:
- The strength of a base is inversely related to the strength of its conjugate acid.
- A stronger acid will have a weaker conjugate base, while a weaker acid will have a stronger conjugate base.

3. **Analyze the Acidity of Each Compound**:
- **Ortho-substituted benzoic acid**: The ortho effect increases acidity due to steric hindrance and electron donation from the methyl group, making it more acidic.
- **Benzoic acid**: This is the baseline with no substituents, having moderate acidity.
- **Meta-substituted benzoic acid**: The methyl group has a lesser effect on acidity compared to the ortho position, making it less acidic than ortho but more acidic than para.
- **Para-substituted benzoic acid**: The methyl group has a stabilizing effect through hyperconjugation, making it the least acidic among the four.

4. **Order of Acidity**:
Based on the analysis, the order of acidity from strongest to weakest is:
- Ortho > Benzoic Acid > Meta > Para

5. **Determine the Basicity**:
Since basicity is inversely related to acidity, the order of basic strength (strongest base to weakest base) will be the reverse of the acidity order:
- Para (strongest base) > Meta > Benzoic Acid > Ortho (weakest base)

6. **Conclusion**:
The strongest base among the given options is the para-substituted benzoic acid derivative.

### Final Answer:
The strongest base is the para-substituted benzoic acid derivative.

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