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

Step 1: Plan the matching.
Each name reaction has a unique reagent and product, so I just recognise each one and pair it.

Step 2: Cannizzaro reaction.
Benzaldehyde with concentrated NaOH disproportionates into benzyl alcohol and sodium benzoate. That is reaction $(q)$. So $(a)-(q)$.

Step 3: Carbylamine reaction.
A primary amine like aniline with chloroform and alcoholic KOH gives a foul-smelling isocyanide. That is reaction $(s)$. So $(b)-(s)$.

Step 4: Gattermann reaction.
Here a diazonium salt with $Cu/HBr$ gives the aryl bromide. That is reaction $(p)$. So $(c)-(p)$.

Step 5: Sandmeyer reaction.
A diazonium salt with $CuCN/KCN$ gives the aryl nitrile. That is reaction $(r)$. So $(d)-(r)$.

Step 6: Final pairing.
Putting it together gives $(a)-(q), (b)-(s), (c)-(p), (d)-(r)$.
\[ \boxed{(a)-(q),\ (b)-(s),\ (c)-(p),\ (d)-(r)} \]