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 solve the question of what product is formed when benzaldehyde is treated with NaOD in D2O, we will follow these steps:

### Step 1: Identify the Reactants
Benzaldehyde (C6H5CHO) is our starting material. It contains a carbonyl group (C=O) attached to a benzene ring. NaOD is sodium deuteroxide, which is the deuterated form of sodium hydroxide, and D2O is deuterium oxide, also known as heavy water.

**Hint:** Identify the structure of benzaldehyde and the nature of the reagents used.

### Step 2: Understand the Reaction Mechanism
The reaction follows the mechanism of the Cannizzaro reaction, which occurs in aldehydes that do not have alpha-hydrogens. In this case, benzaldehyde lacks alpha-hydrogens.

**Hint:** Recall that the Cannizzaro reaction involves disproportionation of aldehydes without alpha-hydrogens.

### Step 3: Nucleophilic Attack
In the Cannizzaro reaction, the deuteroxide ion (OD-) from NaOD will act as a nucleophile and attack the carbonyl carbon of benzaldehyde. This forms a tetrahedral intermediate.

**Hint:** The nucleophile (OD-) attacks the electrophilic carbon in the carbonyl group.

### Step 4: Formation of the Intermediate
After the nucleophilic attack, the tetrahedral intermediate will collapse, leading to the formation of benzyl alcohol (C6H5CH2OD) and benzoate ion (C6H5COO-).

**Hint:** The tetrahedral intermediate will rearrange to form the products.

### Step 5: Final Products
The products of the reaction are:
1. Benzyl alcohol (C6H5CH2OD) where the hydroxyl group is replaced by deuterium.
2. Sodium benzoate (C6H5COO-Na).

**Hint:** Identify the final products based on the reaction mechanism.

### Step 6: Summarize the Reaction
The overall reaction can be summarized as:
- Benzaldehyde reacts with NaOD in D2O to produce benzyl alcohol (C6H5CH2OD) and sodium benzoate (C6H5COO-Na).

**Hint:** Write down the balanced equation to visualize the reactants and products clearly.

### Conclusion
The final products when benzaldehyde is treated with NaOD in D2O are benzyl alcohol (C6H5CH2OD) and sodium benzoate (C6H5COO-Na).