Cannizzaro's reaction is not given by _________ .

Options

A.
B.
C. HCHO
D. `CH_(3)CHO`

Answer

To answer the question "Cannizzaro's reaction is not given by _________", we need to understand the conditions under which Cannizzaro's reaction occurs and identify the aldehyde that does not participate in this reaction.

### Step-by-Step Solution:

1. **Understanding Cannizzaro's Reaction**:
- Cannizzaro's reaction is a redox reaction that occurs in aldehydes that do not have alpha-hydrogens. In this reaction, one molecule of the aldehyde is oxidized to a carboxylic acid, while another molecule is reduced to an alcohol.

2. **Identifying Aldehydes**:
- Aldehydes can be classified based on the presence or absence of alpha-hydrogens. Aldehydes with at least one alpha-hydrogen will not undergo Cannizzaro's reaction.

3. **Examples of Aldehydes**:
- Formaldehyde (HCHO) does not have alpha-hydrogens and can undergo Cannizzaro's reaction.
- Acetaldehyde (CH3CHO) has alpha-hydrogens and cannot undergo Cannizzaro's reaction.
- Benzaldehyde (C6H5CHO) also does not have alpha-hydrogens and can undergo Cannizzaro's reaction.
- Propionaldehyde (C2H5CHO) has alpha-hydrogens and cannot undergo Cannizzaro's reaction.

4. **Analyzing the Options**:
- Given the options (let's assume they are A, B, C, and D), we need to determine which aldehyde does not participate in Cannizzaro's reaction.
- If one of the options is an aldehyde with alpha-hydrogens, that would be the correct answer.

5. **Conclusion**:
- Based on the understanding that aldehydes with alpha-hydrogens do not undergo Cannizzaro's reaction, we can conclude that the correct answer is the aldehyde that has alpha-hydrogens.

### Final Answer:
Cannizzaro's reaction is not given by aldehydes that contain alpha-hydrogens, such as Acetaldehyde (if it is one of the options).

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