Question

What is the name of the reaction?
${\text{RCN}}\,\mathop {\mathop \to \limits_{{\text{(II)}}{{\text{H}}_{\text{3}}}{{\text{O}}^{\text{ + }}}} }\limits^{{\text{(I)SNC}}{{\text{l}}_{\text{2}}}{\text{ + HCl}}} \,{\text{ROH}}$
A. Rosenmund
B. Williamson
C. Stephen
D. Kolbe

Answer 1

Hint:To determine the answer we should know the reactant, products and reagents of the given name reactions. Rosenmund reaction is used to convert the acyl chloride into aldehyde. Williamson synthesis is used to convert alkyl halide into ether. Stephen reaction is used for the reduction of cyanide. Kolbe reaction is used for carboxylation.

Complete step by step answer:
Rosenmund reduction:
In Rosenmund reduction, the reactant is acyl chloride and the product is aldehyde. The reagent used in Rosenmund reduction is hydrogen in presence of lead and barium sulphate. The reaction is represented as follows:
${\text{RC(O)Cl}}\,\mathop {\mathop \to \limits_{{\text{Pb - BaS}}{{\text{O}}_4}} }\limits^{{{\text{H}}_2}} \,{\text{ROH}}$
So, the given reaction is not Rosenmund reduction.

-Williamson ether synthesis:
In Williamson ether synthesis, reactant is alkyl halide and product is ether. The reagent used in Williamson ether synthesis is base. The reaction is represented as follows:
${\text{R}} - {\text{O}} - {\text{Cl}}\,{\text{ + }}\,{\text{R}} - {\text{X}}\,\,\mathop \to \limits^{{\text{Base}}} \,{\text{R}} - {\text{O}} - {\text{R}}$
So, the given reaction is not Williamson ether synthesis.

-Stephen reduction:
In Stephen reduction, reactant is nitriles and the product is aldehyde. The reagent used in Stephen reduction is tin (II) chloride with hydrochloric acid and water. The reaction is represented as follows:
${\text{RCN}}\,\mathop {\mathop \to \limits_{{\text{(II)}}{{\text{H}}_{\text{3}}}{{\text{O}}^{\text{ + }}}} }\limits^{{\text{(I)SNC}}{{\text{l}}_{\text{2}}}{\text{ + HCl}}} \,{\text{ROH}}$
So, the given reaction is Stephen reduction.

-Kolbe reaction:
In Kolbe reaction, the reactant is phenol and the product is carboxylic acid. The reagent used in Kolbe reaction is carbon dioxide and base like sodium hydroxide. The reaction is represented as follows:
${\text{Ph}}\,{\text{ - OH}}\,\mathop {\mathop \to \limits_{{\text{(II)}}{{\text{H}}_{\text{3}}}{{\text{O}}^{\text{ + }}}} }\limits^{{\text{C}}{{\text{O}}_2},{\text{NaOH}}} \,{\text{Ph(COOH)OH}}$


So, the given reaction is not a Kolbe reaction.
So, the name of the given reaction is Stephen.

Therefore, option (C) Stephen, is correct.

Note: Stephen and Rosenmund reactions are the reduction reaction. Tin (II) chloride and hydrogen in presence of lead and barium sulphate are reducing agents. The hydrogen with lead and barium sulphate is known as Rosenmund catalyst and it is used for hydrogenation. Hydrogen with lead only is known as Lindlar catalyst.