A colourless substance ‘A’ (C6H7N) is sparingly soluble in water and gives a water soluble compound ‘B’ on treating with mineral acid. On reacting with CHCl3 and alcoholic potash ‘A’ produces an obnoxious smell due to the formation of compound ‘C’. Reaction of ‘A’ with benzenesulphonyl chloride gives compound ‘D’ which is soluble in alkali. With NaNO2 and HCl, ‘A’ forms compound ‘E’ which reacts with phenol in alkaline medium to give an orange dye ‘F’. Identify compounds ‘A’ to ‘F’.

Question

A colourless substance ‘A’ (C6H7N) is sparingly soluble in water and gives a water soluble compound ‘B’ on treating with mineral acid. On reacting with CHCl3 and alcoholic potash ‘A’ produces an obnoxious smell due to the formation of compound ‘C’. Reaction of ‘A’ with benzenesulphonyl chloride gives compound ‘D’ which is soluble in alkali. With NaNO2 and HCl, ‘A’ forms compound ‘E’ which reacts with phenol in alkaline medium to give an orange dye ‘F’. Identify compounds ‘A’ to ‘F’.

Philoid · Accepted Answer

Firstly, when compound ‘A’ reacts with benzenesulphonyl chloride, it gives a compound which is soluble in alkali. That means the compound is a primary amine. ‘A’ is given as C₆H₇N or C₆H₅NH₂.

Compound ‘A’ is C₆H₅NH₂ or aniline if it is a primary amine, which can be proven in the following reactions. Aniline is sparingly soluble in water.

Since aniline is basic, on reaction with mineral acid like HCl, it gives compound ‘B’ which is anilium chloride which is a salt and is soluble in water.

When aniline reacts with chloroform, CHCl₃ and alcoholic potash, KOH, it forms benzene isonitrile or compound ‘C’ which has an obnoxious smell.

As mentioned above, aniline reacts with benzenesulphonyl chloride to give compound ‘D’ or N-phenylbenzenesulphonamide which is soluble in alkali.

When aniline reacts with NaNO₂ and HCl, it forms diazonium salt ie. benzene diazonium chloride, which on reaction with phenol in alkaline conditions gives an orange dye ‘F’ which is p-hydroxyazobenzone.