In the reaction,
`C_(6)H_(5)NH_(2)underset(0-5^(@)C)overset(NaNO_(2)+HCl)rarr(A)underset(KCN)overset(CuCN)rarr(B)overset(H^(+)//H_(2)O)rarr(C)`
the product `( C)` is

Options

A. `C_(6)H_(5)CH_(2)NH_(2)`
B. `C_(6)H_(5)COOH`
C. `C_(6)H_(5)OH`
D. none of these

Explanation

To solve the problem step by step, we will analyze the reactions involved in the transformation of aniline (C6H5NH2) to the final product (C).

### Step 1: Formation of Diazonium Salt
- **Starting Compound**: C6H5NH2 (aniline)
- **Reagents**: NaNO2 (sodium nitrite) and HCl (hydrochloric acid) at 0-5 °C.
- **Reaction**: When aniline reacts with sodium nitrite and hydrochloric acid at low temperatures, it forms benzene diazonium chloride (C6H5N2Cl).

**Chemical Equation**:
\[ C_6H_5NH_2 + NaNO_2 + HCl \rightarrow C_6H_5N_2Cl + NaCl + 2H_2O \]

### Step 2: Sandmeyer Reaction
- **Intermediate Compound**: C6H5N2Cl (benzene diazonium chloride)
- **Reagents**: CuCN (copper(I) cyanide) and KCN (potassium cyanide).
- **Reaction**: The diazonium salt undergoes a Sandmeyer reaction to form benzonitrile (C6H5CN) and nitrogen gas (N2).

**Chemical Equation**:
\[ C_6H_5N_2Cl + CuCN \rightarrow C_6H_5CN + N_2 + CuCl \]

### Step 3: Hydrolysis of Benzonitrile
- **Intermediate Compound**: C6H5CN (benzonitrile)
- **Reagents**: H+ (acid) and H2O (water).
- **Reaction**: Benzonitrile undergoes hydrolysis in the presence of acid to form benzoic acid (C6H5COOH).

**Chemical Equation**:
\[ C_6H_5CN + H_2O + H^+ \rightarrow C_6H_5COOH + NH_4^+ \]

### Final Product
- The final product (C) is benzoic acid, which can be represented as C6H5COOH.

### Summary of the Reaction Sequence
1. **Aniline (C6H5NH2)** → **Benzene diazonium chloride (C6H5N2Cl)**
2. **Benzene diazonium chloride (C6H5N2Cl)** → **Benzonitrile (C6H5CN)**
3. **Benzonitrile (C6H5CN)** → **Benzoic acid (C6H5COOH)**

### Final Answer
The product (C) is **C6H5COOH (benzoic acid)**.

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