Which of the following acts as a nucleophilie in the Cannizzaro reaction involving benzaldehyde ?
(i) `OH^(-)" (ii) "overset(-)(C_(6))H_(4)COH`
(iii) `C_(6)H_(5)CH(OH)O^(-)" (iv) "H_(2)overset(* *)O:`

Options

A. (i) and (iv)
B. (i) and (ii)
C. (i) and (iii)
D. only (i)

Explanation

To determine which species acts as a nucleophile in the Cannizzaro reaction involving benzaldehyde, we need to analyze each option provided.

### Step-by-Step Solution:

1. **Understanding the Cannizzaro Reaction**:
The Cannizzaro reaction occurs with aldehydes that do not have alpha hydrogens. Benzaldehyde (C₆H₅CHO) is one such aldehyde. In this reaction, one molecule of benzaldehyde is oxidized to benzoic acid, while another molecule is reduced to benzyl alcohol.

2. **Identifying Nucleophiles**:
In the Cannizzaro reaction, a nucleophile attacks the carbonyl carbon of the aldehyde. The common nucleophile in this reaction is the hydroxide ion (OH⁻).

3. **Analyzing Each Option**:
- **(i) OH⁻**: This is a hydroxide ion, which is a strong nucleophile and can attack the carbonyl carbon of benzaldehyde.
- **(ii) C₆H₄COH**: This represents a benzyl alcohol structure. While it can participate in the reaction, it is not a nucleophile in the context of the Cannizzaro reaction.
- **(iii) C₆H₅CH(OH)O⁻**: This is a species that can act as a nucleophile due to the presence of the negatively charged oxygen. It can also participate in the reaction.
- **(iv) H₂O**: Water is a very weak nucleophile and does not effectively participate in the Cannizzaro reaction.

4. **Conclusion**:
The species that acts as a nucleophile in the Cannizzaro reaction involving benzaldehyde are:
- **(i) OH⁻**
- **(iii) C₆H₅CH(OH)O⁻**

Thus, the correct options are (i) and (iii).

### Final Answer:
The nucleophiles in the Cannizzaro reaction involving benzaldehyde are (i) `OH⁻` and (iii) `C₆H₅CH(OH)O⁻`.

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