Write the structures of compounds A, B and C in the following reactions:

(a)

(b)

(a)

When CH₃COOH is treated with ammonia, first it forms ammonium

salt, which upon heating lose a molecule of water to from acid

amide (CO—NH₂ group)

Hence, A will be CH₃CONH₂

Now, CH₃CONH₂ (A) is treated with Br₂/KOH, it gives a primary

amine which has one carbon less than the original amide.

Hence, B will be CH₃—NH₂

Now, CH₃—NH₂ (B) is treated with CHCl₃ and alcoholic KOH, it gives

Isocyanides or carbylamines which have very unpleasant odour.

This reaction is called carbylamine reaction.

Hence, C will be CH₃NC

(b)

When (arenediazonium fluoroborate) is treated with an

aqueous solution sodium nitrite(NaNO₂) in the presence of Cu

powder, it forms Nitrobenzene by the removal of N₂ and NaBF₄.

Hence, A will be C₆H₅NO₂

Now, C₆H₅NO₂ (A) is treated with Fe and HCl, it gives aniline

Hence, B will be C₆H₅NH₂

Now, C₆H₅NH₂ (B) is treated with CH₃COCl in the presence of

pyridine, it gives C₆H₅—NH—CO—CH₃. This reaction is called

acetylation reaction.

Hence, C will be C₆H₅—NH—CO—CH₃