The reagent which does not react with both acetone and benzaldehyde is

Options

A. Sodium hydrogen sulphite
B. Phenyl hydrazine
C. Fehling's solution
D. Grignard reagent

Explanation

To solve the question regarding which reagent does not react with both acetone and benzaldehyde, we can follow these steps:

### Step 1: Identify the Functional Groups
- **Acetone**: Acetone has a ketone functional group (C=O) since it is a simple ketone.
- **Benzaldehyde**: Benzaldehyde has an aldehyde functional group (C=O) and is also an aromatic compound.

### Step 2: Analyze the Reagents
We need to evaluate the reactivity of the given reagents with both acetone and benzaldehyde. The reagents mentioned in the video are:
1. Sodium hydrogen sulfite (NaHSO3)
2. Phenylhydrazine
3. Fehling's solution

### Step 3: Check Reactivity with Acetone and Benzaldehyde
1. **Sodium Hydrogen Sulfite (NaHSO3)**:
- This reagent reacts with both ketones (like acetone) and aldehydes (like benzaldehyde) to form addition products.

2. **Phenylhydrazine**:
- This reagent also reacts with both ketones and aldehydes to form hydrazones. Therefore, it will react with both acetone and benzaldehyde.

3. **Fehling's Solution**:
- Fehling's solution is used to differentiate between aldehydes and ketones. It does not react with ketones, including acetone, and does not react with aromatic aldehydes like benzaldehyde.

### Step 4: Conclusion
Based on the analysis, **Fehling's solution** does not react with either acetone or benzaldehyde. Therefore, the correct answer is:

**Fehling's solution (C)** is the reagent that does not react with both acetone and benzaldehyde.

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