What will be the product when benzaldehyde is treated with NaOD in `D_2O` ?

Options

A. `C_2H_5CH_2OD and C_6H_5COONa`
B. `C_2H_5CH_2OD and C_6H_5COOD`
C. `C_6H_5CHDOD and C_6H_5COONa`
D. `C_6H_5COOCHDC_6H_5`

Answer

To determine the product when benzaldehyde is treated with NaOD in D₂O, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**: We have benzaldehyde (C₆H₅CHO) and sodium deuteroxide (NaOD) in deuterium oxide (D₂O).

2. **Understand the Reaction Type**: The reaction involves a Cannizzaro reaction, which occurs with aldehydes that do not have alpha-hydrogens. In this reaction, one molecule of benzaldehyde will be oxidized to form a carboxylate ion, while another molecule will be reduced to form an alcohol.

3. **Reaction Mechanism**:
- **Step 1**: The deuteroxide ion (OD⁻) attacks the carbonyl carbon of benzaldehyde. This forms a tetrahedral intermediate. The oxygen of the carbonyl group becomes negatively charged (alkoxide).
- **Step 2**: The tetrahedral intermediate collapses, leading to the formation of a carboxylate ion (C₆H₅COO⁻) and a benzyl alcohol (C₆H₅CH₂OD). The hydrogen atom from the benzaldehyde is replaced by deuterium from D₂O.

4. **Final Products**: The products of the reaction are:
- Sodium benzoate (C₆H₅COO⁻Na⁺)
- Benzyl alcohol with deuterium (C₆H₅CH₂OD)

5. **Conclusion**: The final products of the reaction are sodium benzoate (C₆H₅COONa) and benzyl alcohol with a deuterium atom (C₆H₅CH₂OD).

### Answer:
The products are:
- Sodium benzoate (C₆H₅COONa)
- Benzyl alcohol with deuterium (C₆H₅CH₂OD)