The molecule that can give Cannizzaro's reaction is

Options

A. acetaldehyde
B. formaldehyde
C. butyraldehyde
D. propionaldehyde

Explanation

To determine which molecule can give Cannizzaro's reaction, we need to understand the conditions under which this reaction occurs. Cannizzaro's reaction is a redox reaction that occurs with aldehydes that do not have alpha-hydrogens.

### Step-by-Step Solution:

1. **Understanding Cannizzaro's Reaction**:
- Cannizzaro's reaction involves the disproportionation of non-enolizable aldehydes in the presence of a strong base, typically resulting in the formation of an alcohol and a carboxylic acid.

2. **Identifying Aldehydes**:
- Aldehydes are organic compounds containing the functional group -CHO.
- For Cannizzaro's reaction to occur, the aldehyde must lack alpha-hydrogens. Alpha-hydrogens are the hydrogen atoms attached to the carbon adjacent to the carbonyl carbon.

3. **Analyzing the Given Options**:
- We need to analyze the given options to identify which aldehyde does not have alpha-hydrogens.

- **Option A**: Acetaldehyde (CH3CHO) - This has an alpha-hydrogen (the methyl group has three hydrogens).
- **Option B**: Formaldehyde (HCHO) - This does not have any alpha-hydrogens since it is a one-carbon aldehyde.
- **Option C**: Butyraldehyde (C3H7CHO) - This has alpha-hydrogens (the propyl group has hydrogens).
- **Option D**: 2-Butenal - This is not an aldehyde but an alkene, so it does not apply.

4. **Conclusion**:
- Among the options, **Formaldehyde (HCHO)** is the only molecule that can undergo Cannizzaro's reaction because it lacks alpha-hydrogens.

### Final Answer:
The molecule that can give Cannizzaro's reaction is **Formaldehyde (HCHO)**.