Which of the following is not the mechanism of Cannizzaro reaction ?
`2PhCHO overset(overset(Θ)(OH))rarr PhCH_(2)OH+PhCOO^(Θ)`

Options

A. The attack of `overset(Θ)(OH)` at the `(C=O)` group.
B. The transfer of `H^(Θ)` ion the `(C=O)` group.
C. The abstraction of `H^(o+)` ion from carboxylic acid.
D. The deprotonation of `PhCH_(2)OH`.

Answer

To determine which of the following is not a mechanism of the Cannizzaro reaction, we need to understand the Cannizzaro reaction itself. The Cannizzaro reaction occurs with aldehydes that do not have alpha hydrogens, leading to the disproportionation of the aldehyde into an alcohol and a carboxylic acid.

### Step-by-Step Solution:

1. **Understanding the Cannizzaro Reaction**:
- The Cannizzaro reaction involves aldehydes that lack 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. **Mechanism Steps**:
- **Step 1: Nucleophilic Attack**:
- The hydroxide ion (OH-) attacks the carbonyl carbon of the aldehyde (PhCHO). This forms a tetrahedral intermediate where the carbon becomes positively charged, and the oxygen becomes negatively charged.
- **Step 2: Hydride Transfer**:
- In the next step, the negatively charged oxygen donates electrons back to the carbon, leading to the transfer of a hydride ion (H-) from one aldehyde molecule to another. This results in the formation of a carboxylic acid (PhCOOH) and an alcohol (PhCH2OH).
- **Step 3: Formation of Products**:
- The final products are the alcohol (PhCH2OH) and the carboxylate ion (PhCOO-).

3. **Evaluating the Statements**:
- Now, we need to evaluate the provided statements regarding the mechanism:
- **A**: The attack of the hydroxyl group at the carbonyl carbon – This is correct.
- **B**: The transfer of hydride ion – This is also correct.
- **C**: The abstraction of H+ ion from the carboxylic acid – This is correct as the carboxylic acid can lose a proton.
- **D**: The deprotonation of benzyl alcohol – This is incorrect, as benzyl alcohol is formed as a product and does not undergo deprotonation in this reaction.

4. **Conclusion**:
- The statement that is not part of the Cannizzaro reaction mechanism is **D: The deprotonation of benzyl alcohol**.

### Final Answer:
The statement that is not the mechanism of the Cannizzaro reaction is **D**.