Identify Y in the reaction,
`C_(6)H_(5)NH_(2) underset(273K)overset(NaNO_(2)//HCl)to X underset(dil." "H_(2)SO_(4))overset(H_(2)O)toY`

Options

A. `phi - overset(o+)(N_(2))overset(Theta)(CI)`
B. `phi - N =C`
C. `phi - NH(CH_(3))`
D. `phi - CN`

Answer

To identify Y in the given reaction sequence, let's break down the steps involved:

### Step 1: Identify the starting material
The starting material is aniline, which has the chemical formula \( C_6H_5NH_2 \).

### Step 2: Reaction with nitrous acid
When aniline is treated with nitrous acid (which is generated from sodium nitrite \( NaNO_2 \) and hydrochloric acid \( HCl \)), it undergoes diazotization. The reaction can be represented as follows:

\[ C_6H_5NH_2 + NaNO_2 + HCl \rightarrow C_6H_5N_2Cl + H_2O \]

The product formed here is benzene diazonium chloride, which is represented as \( C_6H_5N_2^+Cl^- \). This compound is known as product X.

### Step 3: Hydrolysis of benzene diazonium chloride
The next step involves the hydrolysis of benzene diazonium chloride in the presence of dilute sulfuric acid \( H_2SO_4 \) and water. The reaction can be represented as:

\[ C_6H_5N_2Cl + H_2O \xrightarrow{dil. H_2SO_4} C_6H_5OH + HCl + N_2 \]

During this hydrolysis, benzene diazonium chloride is converted into phenol (\( C_6H_5OH \)).

### Conclusion
Thus, the final product Y in the reaction sequence is phenol.

\[ \text{Y} = C_6H_5OH \text{ (Phenol)} \]