Which of the following will not undergo aldol condensation?

Options

A. Acetaldehyde
B. Propanaldehyde
C. Benzaldehyde
D. Propanone

Answer

To determine which compound will not undergo aldol condensation, we need to analyze the provided options based on the criteria for aldol condensation reactions. Here’s a step-by-step solution:

### Step 1: Understand Aldol Condensation
Aldol condensation is a reaction that occurs between aldehydes or ketones that have at least one alpha hydrogen. An alpha hydrogen is a hydrogen atom attached to the carbon adjacent to the carbonyl group (C=O).

### Step 2: Identify the Options
Let’s assume the options are:
- A: Acetaldehyde (CH3CHO)
- B: Propanal (CH3CH2CHO)
- C: Benzaldehyde (C6H5CHO)
- D: Acetone (CH3COCH3)

### Step 3: Analyze Each Compound
1. **Acetaldehyde (A)**:
- Structure: CH3CHO
- Alpha Carbon: The carbon next to the carbonyl (C=O) is CH3, which has 3 alpha hydrogens.
- Conclusion: Can undergo aldol condensation.

2. **Propanal (B)**:
- Structure: CH3CH2CHO
- Alpha Carbon: The carbon next to the carbonyl (C=O) is CH2, which has 2 alpha hydrogens.
- Conclusion: Can undergo aldol condensation.

3. **Benzaldehyde (C)**:
- Structure: C6H5CHO
- Alpha Carbon: The carbon next to the carbonyl is part of the benzene ring and has no hydrogen atoms attached (the carbon is fully substituted).
- Conclusion: Cannot undergo aldol condensation.

4. **Acetone (D)**:
- Structure: CH3COCH3
- Alpha Carbon: The carbons next to the carbonyl (C=O) are both CH3, each having 3 alpha hydrogens.
- Conclusion: Can undergo aldol condensation.

### Step 4: Identify the Answer
Based on the analysis, the compound that will not undergo aldol condensation is **C: Benzaldehyde**.

### Final Answer
**C: Benzaldehyde will not undergo aldol condensation.**

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