Which of the following undergoes cannizaro reaction ?
A)HCHO B) ` C_(6)H_(5)CHO`
C) `Cl_(3)C-CHO` D) ` (CH_(3))_(3)C-CHO`

Options

A. Only A & B
B. Only B & C
C. Only C & D
D. Only A,B & D

Explanation

To determine which of the given compounds undergoes the Cannizzaro reaction, we need to understand the conditions under which this reaction occurs. The Cannizzaro reaction typically takes place with aldehydes that do not have alpha-hydrogens.

### Step-by-Step Solution:

1. **Identify the Compounds:**
- A) HCHO (Formaldehyde)
- B) C₆H₅CHO (Benzaldehyde)
- C) Cl₃C-CHO (Trichloroacetaldehyde)
- D) (CH₃)₃C-CHO (tert-Butylaldehyde)

2. **Check for Alpha-Hydrogens:**
- **A) HCHO:**
- Structure: H-C(=O)-H
- Alpha Carbon: None (no carbon adjacent to the carbonyl carbon)
- Alpha Hydrogens: 0
- Conclusion: Can undergo Cannizzaro reaction.

- **B) C₆H₅CHO:**
- Structure: C₆H₅-C(=O)-H
- Alpha Carbon: None (the carbonyl carbon is directly attached to a phenyl group)
- Alpha Hydrogens: 0
- Conclusion: Can undergo Cannizzaro reaction.

- **C) Cl₃C-CHO:**
- Structure: Cl₃C-C(=O)-H
- Alpha Carbon: None (the carbonyl carbon is attached to a trichloromethyl group)
- Alpha Hydrogens: 0
- Conclusion: Can undergo Cannizzaro reaction.

- **D) (CH₃)₃C-CHO:**
- Structure: (CH₃)₃C-C(=O)-H
- Alpha Carbon: (CH₃)₃C has three methyl groups attached to the carbon adjacent to the carbonyl carbon.
- Alpha Hydrogens: 9 (from the three methyl groups)
- Conclusion: Cannot undergo Cannizzaro reaction.

3. **Final Conclusion:**
- The compounds that can undergo the Cannizzaro reaction are A) HCHO, B) C₆H₅CHO, and C) Cl₃C-CHO.
- The compound D) (CH₃)₃C-CHO does not undergo the Cannizzaro reaction due to the presence of alpha-hydrogens.

### Answer:
The compounds that undergo Cannizzaro reaction are:
- A) HCHO
- B) C₆H₅CHO
- C) Cl₃C-CHO