Which of the following will undergo aldol condensation?

Options

A. `CH_(2) = CHCHO`
B. `CH -= C CHO`
C. `C_(6)H_(5)CHO`
D. `CH_(3)CH_(2)CHO ?`

Explanation

To determine which of the given compounds will undergo aldol condensation, we must first understand the requirements for this reaction. Aldol condensation typically occurs when a compound has at least one alpha-hydrogen adjacent to a carbonyl group (aldehyde or ketone). The presence of alpha-hydrogens allows for the formation of an enolate ion, which is crucial for the aldol reaction.

### Step-by-Step Solution:

1. **Identify the Compounds**: List the compounds provided in the question. For this example, let's assume the options are:
- A) CH2=CHCHO (Acrolein)
- B) CH≡CCHO (Propyne)
- C) C6H5CHO (Benzaldehyde)
- D) C6H3CH2CHO (Substituted benzaldehyde)

2. **Check for Alpha-Hydrogens**:
- **Option A (CH2=CHCHO)**: This compound has alpha-hydrogens on the carbon adjacent to the carbonyl (CHO) group. Therefore, it can undergo aldol condensation.
- **Option B (CH≡CCHO)**: This compound also has alpha-hydrogens on the carbon adjacent to the carbonyl group. Thus, it can also undergo aldol condensation.
- **Option C (C6H5CHO)**: Benzaldehyde has no alpha-hydrogens because the carbon adjacent to the carbonyl is part of the phenyl ring. Therefore, it cannot undergo aldol condensation.
- **Option D (C6H3CH2CHO)**: This compound has alpha-hydrogens on the carbon adjacent to the carbonyl group, allowing it to undergo aldol condensation.

3. **Conclusion**: The compounds that can undergo aldol condensation are:
- A) CH2=CHCHO (Acrolein)
- B) CH≡CCHO (Propyne)
- D) C6H3CH2CHO (Substituted benzaldehyde)

### Final Answer:
The compounds that will undergo aldol condensation are:
- A) CH2=CHCHO
- B) CH≡CCHO
- D) C6H3CH2CHO