Phenylglyoxal, `(C_(6)H_(5)COCHO)`, on heating with concentrated NaOH gives:

Options

A. `C_6H)5COONa and CH_3OH`
B. `C_6H_5CH_2OH and HCOONa`
C. `C_6H_5CHOHCOONa`
D. `C_6H_5COONa and HCOONa`

Answer

To solve the problem of what phenylglyoxal `(C6H5COCHO)` produces when heated with concentrated NaOH, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Structure of Phenylglyoxal**:
- Phenylglyoxal has the structure `C6H5COCHO`, which consists of a phenyl group (`C6H5`), a carbonyl group (`C=O`), and an aldehyde group (`CHO`).

2. **Understand the Reaction with NaOH**:
- When phenylglyoxal is heated with concentrated NaOH, the hydroxide ion (`OH-`) acts as a nucleophile.

3. **Nucleophilic Attack**:
- The hydroxide ion attacks the carbonyl carbon of the aldehyde group. This leads to the formation of a tetrahedral intermediate where the double bond between carbon and oxygen breaks, and a negative charge is created on the oxygen.

4. **Proton Transfer**:
- In the tetrahedral intermediate, there is a possibility of resonance. The negative charge on the oxygen can stabilize itself by transferring a proton (H+) from the hydroxyl group to the carbon adjacent to the carbonyl, leading to the formation of a carboxylate ion.

5. **Formation of the Final Product**:
- The final product after the reaction will be a sodium salt of the carboxylic acid formed from the reaction. The structure will be `C6H5CHOHCOONa`, which is the sodium salt of phenylglyoxal.

6. **Conclusion**:
- Therefore, the product of the reaction of phenylglyoxal with concentrated NaOH is `C6H5CHOHCOONa`.

### Final Answer:
The product formed is `C6H5CHOHCOONa`.