Question

Consider the following reaction sequence \[ \textit{p}\text{-Toluidine} \xrightarrow[\;273\text{--}278\,\mathrm{K}\;]{\mathrm{NaNO_2+HCl}} \xrightarrow{X} Y \] Identify the set(s) in which \(X\) and \(Y\) are correctly arranged. 

The correct answer is

• A. I, II only
• B. II only
• C. I, III only
• D. III only

Hint:

Important reactions of aryl diazonium salts: \[ \boxed{ \mathrm{CuCN} \rightarrow \mathrm{-CN} } \] \[ \boxed{ \mathrm{CuBr} \rightarrow \mathrm{-Br} } \] \[ \boxed{ \mathrm{H_3PO_2} \rightarrow \mathrm{-H} } \]

Answer 1

The Correct Option is A

Step 1: Formation of diazonium salt. p-Toluidine on treatment with \[ \mathrm{NaNO_2/HCl} \] at \[ 273\text{--}278\ \mathrm{K} \] forms \[ \boxed{p\text{-methyl benzene diazonium chloride}.} \]

Step 2: Check Set-I. Treatment with \[ \mathrm{CuCN/KCN} \] (Sandmeyer reaction) gives \[ p\text{-methyl benzonitrile}. \] Hydrolysis converts it into \[ \boxed{p\text{-methyl benzoic acid}.} \] Hence, \[ \boxed{\text{Set-I is correct}.} \]

Step 3: Check Set-II. Reaction with \[ \mathrm{CuBr/HBr} \] forms \[ p\text{-bromotoluene}. \] Oxidation using \[ \mathrm{KMnO_4/OH^-} \] followed by acidification converts the methyl group into \[ \boxed{p\text{-bromobenzoic acid}.} \] Hence, \[ \boxed{\text{Set-II is correct}.} \]

Step 4: Check Set-III. \[ \mathrm{H_3PO_2} \] reduces the diazonium group to hydrogen, producing toluene, not anisole. Hence, \[ \boxed{\text{Set-III is incorrect}.} \] Therefore, \[ \boxed{\text{I and II only}} \] are correct. Thus, \[ \boxed{(A)} \] is the correct answer.