An unknown amide 'A' undergoes Hoffmann bromamide degradation to give an amine 'B'. Treatment of 'B' with nitrous acid yields an alcohol 'C'. When 'C' is reacted with benzenediazonium chloride, it yields benzene and a carbonyl compound 'D'. If compound 'D' gives a positive iodoform test but a negative Tollen's test, identify the starting amide 'A'.

Step-by-step solution

Compound 'D' gives a positive iodoform test but a negative Tollen's test, indicating it is a methyl ketone and not an aldehyde. The simplest methyl ketone is acetone (propanone), CH ₃ COCH ₃ . Since 'D' is formed by the oxidation of alcohol 'C' during the reduction of benzenediazonium chloride, 'C' must be a secondary alcohol, specifically propan-2-ol (isopropyl alcohol). Alcohol 'C' is obtained from the reaction of amine 'B' with nitrous acid. Thus, 'B' must be a primary aliphatic amine, propan-2-amine (isopropyla