Question

Compound A is converted to B on reaction with CHCl₃ and KOH. The compound B is toxic and can be decomposed by C. A, B and C respectively are ______.

Options

• secondary amine, nitrile compound, conc. NaOH 

• primary amine, isonitrile compound, cone. HCl

• secondary amine, isonitrile compound, conc. NaOH

• primary amine, nitrile compound, cone. HCl

Answer 1

Compound A is converted to B on reaction with CHCl₃ and KOH. The compound B is toxic and can be decomposed by C. A, B and C respectively are primary amine, isonitrile compound, cone. HCl.

Explanation:

Given

\[\ce{A + CHCl3 + KOH -> B}\]

The compound B is toxic in nature.

\[\ce{B + C -> Decomposition of B}\]

To identify the correct option, let us have a look at all options one by one.

Isonitrile or isocyanide must be generated as the hazardous chemical B by the reaction of component A with CHC13 and KOH. The Carbylamine reaction, also known as the Hoffmann isocyanide reaction, is a reaction that only primary (1°) amines may produce. This reaction is used for detection of presence of primary amines and known as Saytzeff's isocyanide test. The isocyanide formed during reaction can be detected by offensive smell.

Therefore, product B is isonitrile compound. On decomposition by conc. HCl, it will produce a primary amine and an acid. Therefore, compound C is conc. HCl.

The complete reaction can be represented as:

\[\ce{\underset{(A)}{\underset{1° amine}{R - NH2}} ->[CHCl3] \underset{(B)}{\underset{Isonitrile}{R - \overset{⊕}{N} ≡ \overset{⊖}{C}}}\underset{(C)}{->[H3O^⊕][HCl]} R - NH2 + HCOOH}\]

The secondary and tertiary amines do not give positive Carbylamine reaction. A: Primary amine B: Isonitrile C: Cone. HCl