Which of the following will not undergo aldol condensation ?

Options

A. Propional dehyde
B. Acetone
C. Formaldehyde
D. Acetaldehyde

Answer

To determine which compound will not undergo aldol condensation, we need to understand the requirements for this reaction. Aldol condensation typically occurs in carbonyl compounds that contain at least two alpha hydrogens. Let's analyze the options step by step:

### Step 1: Identify the compounds
Let's consider four compounds that are typically provided as options in such questions. For the sake of this solution, we will assume the following compounds:
1. Propanal (CH3CH2CHO)
2. Acetone (CH3COCH3)
3. Formaldehyde (HCHO)
4. Acetaldehyde (CH3CHO)

### Step 2: Check for alpha hydrogens
- **Propanal (CH3CH2CHO)**:
- The alpha carbon is the one adjacent to the carbonyl group (CHO).
- It has two alpha hydrogens (from CH2), so it can undergo aldol condensation.

- **Acetone (CH3COCH3)**:
- The alpha carbons are the two CH3 groups adjacent to the carbonyl (C=O).
- Each CH3 has three alpha hydrogens, giving a total of six alpha hydrogens. Thus, acetone can undergo aldol condensation.

- **Formaldehyde (HCHO)**:
- This compound has no alpha carbon because there are no carbons adjacent to the carbonyl group.
- Therefore, it has no alpha hydrogens and cannot undergo aldol condensation.

- **Acetaldehyde (CH3CHO)**:
- The alpha carbon is the CH3 group adjacent to the carbonyl (CHO).
- It has three alpha hydrogens, so it can undergo aldol condensation.

### Step 3: Conclusion
Among the four compounds analyzed, formaldehyde (HCHO) is the only compound that does not have any alpha hydrogens and thus will not undergo aldol condensation.

### Final Answer
The compound that will not undergo aldol condensation is **Formaldehyde (HCHO)**.

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