Question

Which of the following gives $RNC$, when reacted with $CHC{l_3}$​ and $KOH$
(A) $RN{H_2}$
(B) ${R_2}NH$
(C) ${R_3}N$
(D) ${R_4}{N^ + }C{l^ - }$

Answer 1

Hint: An organic molecule bearing the functional group -NC is known as an isocyanide. Its prefix is isocyano $(RNC)$ because it is an isomer of a similar nitrile. The nitrogen atom, not the carbon atom, serves as the link between the organic fragment and the isocyanide group. The synthesis of other chemicals uses them as building blocks.

Complete Step by Step Solution:
In order to know that the formula for isocyanide consists of a nitrogen molecule bound to a carbon atom and an alkyl group, with a resonance structure that comprises a triple bond, forming a carbanion and a positive nitrogen particle. If aniline reacts with $CHC{l_3}$and $KOH$, then:
${C_6}{H_5}N{H_2} + CHC{l_3} + 3KOH(alc.)\xrightarrow{\Delta }{C_6}{H_5}N\overrightarrow = C + 3KCl + 3{H_2}O$
Only primary amines produce isocyanide $(RNC)$, the unpleasant-smelling product, when they are combined with chloroform and alkali $(KOH)$. Carbylamine reaction is the name of this process. Among the provided amines, $RN{H_2}$ is a primary amine that reacts with $CHC{l_3}$ and $KOH$ to produce $RNC$.

The reaction is as follow:
$R - N{H_2} + CHC{l_3} + 3KOH \\$
   $\to R - NC + 3KCl + 3HO \\$
Therefore, when $RN{H_2}$ reacted with $CHC{l_3}$and $KOH$then it gives $RNC$.
Thus, the correct option is: (A) $RN{H_2}$.

Note: Since their electronic characteristics are comparable to those of the $CO$ ligand, isocyanides are frequently used as ligands in group $VI$Isocyanides are frequently used to replace $CO$ or other labile ligands. Examples of this straightforward replacement chemistry can be found in the sections mentioned above, and further examples are provided below. The chemistry of coordinated $N - $heterocyclic carbenes produced by cyclization reactions of -functional aryl isocyanides.