In the given sequence of reaction, identify Y
`C_6H_5-overset(O)overset(||)(C )-CH_3 overset(SeO_2)to X underset((ii)H_2O // H^(o+))overset((i)Conc. NaOH//Delta)(rarr)Y`

Options

A. `C_6H_5-CH_2OH`
B. `C_6H_5-COOH`
C. `C_6H_5-CHOH-COOH`
D. `C_6H_5-CO-COOH`

Answer

To identify the compound Y in the given sequence of reactions, we will analyze each step systematically.

### Step 1: Identify the starting compound
The starting compound is given as:
\[ C_6H_5 - C(=O) - CH_3 \]
This is a phenyl group attached to a carbonyl group (C=O) and a methyl group (CH3).

### Step 2: Reaction with Selenium Dioxide (SeO2)
When this compound is treated with selenium dioxide (SeO2), which is an oxidizing agent, it oxidizes the alpha carbon (the carbon next to the carbonyl carbon that has hydrogen) to another carbonyl carbon.

The reaction can be represented as:
\[ C_6H_5 - C(=O) - CH_3 \xrightarrow{SeO_2} C_6H_5 - C(=O) - C(=O) - H \]
This results in the formation of compound X:
\[ X: C_6H_5 - C(=O) - C(=O) - H \]

### Step 3: Reaction with Concentrated NaOH and Heat
Next, compound X is heated with concentrated NaOH and water. In this step, the hydroxide ion (OH-) acts as a nucleophile and attacks the more electrophilic carbonyl carbon.

The reaction can be represented as:
\[ C_6H_5 - C(=O) - C(=O) - H \xrightarrow{NaOH, \Delta} C_6H_5 - C(OH) - C(=O) - H \]
This results in the formation of an intermediate where one of the carbonyl groups is converted to a hydroxyl group.

### Step 4: Elimination of Water
In the next step, the intermediate undergoes dehydration (loss of water) to form a double bond between the carbon atoms. The reaction can be represented as:
\[ C_6H_5 - C(OH) - C(=O) - H \rightarrow C_6H_5 - C(=O) - C(=O) - H \]
This leads to the formation of a compound with a double bond and a hydroxyl group.

### Step 5: Acidic Hydrolysis
Finally, the product is treated with H2 and H+ (acidic conditions), which will protonate the hydroxyl group, resulting in the formation of the final product Y:
\[ Y: C_6H_5 - C(OH) - C(=O) - OH \]
This can also be represented as:
\[ Y: C_6H_5 - CH(OH) - COOH \]
This structure indicates that Y is a compound with a phenyl group, a hydroxyl group, and a carboxylic acid group.

### Conclusion
The final product Y is:
\[ C_6H_5 - CH(OH) - COOH \]