Which of the following gives an alcohol and salt of carboxylic acid when reacted with conc. NaOH .

Options

A. `CH_(3) CHO`
B. `C_(6) H_(5) CHO`
C. `CH_(3) COCH_(3)`
D. `C_(6) H_(5)COCH_(3)`

Answer

To solve the question, we need to identify which compound reacts with concentrated NaOH to produce an alcohol and a salt of a carboxylic acid. This reaction is characteristic of the Cannizzaro reaction, which occurs with aldehydes that do not have alpha-hydrogens.

### Step-by-Step Solution:

1. **Understand the Cannizzaro Reaction**:
The Cannizzaro reaction is a redox reaction where aldehydes without alpha-hydrogens undergo disproportionation in the presence of a strong base (like concentrated NaOH). One molecule is oxidized to a carboxylic acid, while another is reduced to an alcohol.

2. **Identify the Compounds**:
We need to analyze the given options to determine which compound does not have alpha-hydrogens. Alpha-hydrogens are hydrogens attached to the carbon adjacent to the carbonyl (C=O) group.

3. **Check Each Option**:
- **Option A**: CH3CHO (Acetaldehyde)
- It has 3 alpha-hydrogens (from the CH3 group).
- **Conclusion**: This will not undergo the Cannizzaro reaction.

- **Option B**: CH3COCH3 (Acetone)
- It has 6 alpha-hydrogens (from the two CH3 groups).
- **Conclusion**: This will not undergo the Cannizzaro reaction.

- **Option C**: C6H5CHO (Benzaldehyde)
- It has no alpha-hydrogens since the carbonyl carbon is bonded to a benzene ring and has no adjacent carbon with hydrogens.
- **Conclusion**: This can undergo the Cannizzaro reaction.

- **Option D**: C6H5COCH3 (Acetophenone)
- It has 3 alpha-hydrogens (from the CH3 group).
- **Conclusion**: This will not undergo the Cannizzaro reaction.

4. **Final Conclusion**:
Since only **Option C (Benzaldehyde)** does not have alpha-hydrogens, it will react with concentrated NaOH to produce an alcohol (benzyl alcohol) and a salt of a carboxylic acid (benzoate salt).

### Answer:
**Option C: C6H5CHO (Benzaldehyde)** gives an alcohol and a salt of carboxylic acid when reacted with concentrated NaOH.

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