Question

Match the following reactions in Column-II with the names in Column-I. \[ \begin{array}{llll} (a) & \text{Cannizzaro reaction} & (p) & ArN_2^+Cl^- \xrightarrow{Cu/HBr} ArBr \\[10pt] (b) & \text{Carbylamine reaction} & (q) & C_6H_5CHO \xrightarrow{\text{Conc. NaOH}} C_6H_5CH_2OH + C_6H_5COONa \\[10pt] (c) & \text{Gattermann reaction} & (r) & ArN_2^+Cl^- \xrightarrow{CuCN/KCN} ArCN \\[10pt] (d) & \text{Sandmeyer reaction} & (s) & C_6H_5NH_2 \xrightarrow[alc.\,KOH]{CHCl_3,\ \Delta} C_6H_5NC \end{array} \]

• A. \((a)-(q),\ (b)-(s),\ (c)-(r),\ (d)-(p)\)
• B. \((a)-(s),\ (b)-(q),\ (c)-(p),\ (d)-(r)\)
• C. \((a)-(r),\ (b)-(p),\ (c)-(s),\ (d)-(q)\)
• D. \((a)-(q),\ (b)-(s),\ (c)-(p),\ (d)-(r)\)

Hint:

\[ \begin{aligned} \text{Cannizzaro Reaction} &: \text{Conc. NaOH} \\ \text{Carbylamine Reaction} &: CHCl_3 + \text{Alcoholic KOH} \\ \text{Gattermann Reaction} &: Cu/HCl \text{ or } Cu/HBr \\ \text{Sandmeyer Reaction} &: CuCl,\ CuBr,\ CuCN \end{aligned} \]

Answer 1

The Correct Option is D

Concept: Important name reactions of aldehydes, amines and diazonium salts are recognized by their characteristic reagents and products.

Step 1: Identify the Cannizzaro reaction. Benzaldehyde undergoes disproportionation in concentrated NaOH to form benzyl alcohol and sodium benzoate. \[ 2C_6H_5CHO + NaOH \rightarrow C_6H_5CH_2OH + C_6H_5COONa \] This is the

Cannizzaro reaction. \[ (a)\rightarrow(q) \]

Step 2: Identify the Carbylamine reaction. Primary amines react with chloroform and alcoholic KOH to produce isocyanides. \[ C_6H_5NH_2 \xrightarrow[alc.\,KOH]{CHCl_3} C_6H_5NC \] This is the

Carbylamine reaction. \[ (b)\rightarrow(s) \]

Step 3: Identify the Gattermann reaction. Diazonium salts react with Cu/HBr (or Cu/HCl) to form haloarenes. \[ ArN_2^+Cl^- \xrightarrow{Cu/HBr} ArBr \] This is the

Gattermann reaction. \[ (c)\rightarrow(p) \]

Step 4: Identify the Sandmeyer reaction. Diazonium salts react with cuprous salts such as CuCN to form substituted aromatic compounds. \[ ArN_2^+Cl^- \xrightarrow{CuCN} ArCN \] This is the

Sandmeyer reaction. \[ (d)\rightarrow(r) \] \[ \begin{aligned} \text{Cannizzaro reaction} &: (q) \\ \text{Carbylamine reaction} &: (s) \\ \text{Gattermann reaction} &: (p) \\ \text{Sandmeyer reaction} &: (r) \end{aligned} \] Therefore, \[ (a-q),\quad (b-s),\quad (c-p),\quad (d-r) \] \[ \boxed{(a-q),\quad (b-s),\quad (c-p),\quad (d-r)} \] Hence, option \(\mathbf{(D)}\) is correct.