The starting material is propanoic acid (CH3CH2COOH).
In step (i), propanoic acid reacts with NH3 upon heating to form propanamide.
CH3CH2COOHNH3,ΔCH3CH2CONH2
In step (ii), propanamide undergoes Hoffmann bromamide degradation with NaOH and Br2 to form ethylamine.
CH3CH2CONH2NaOH,Br2CH3CH2NH2
In step (iii), ethylamine reacts with nitrous acid (HNO2) to form an unstable diazonium salt, which hydrolyzes to give ethanol.
CH3CH2NH2HNO2,H2OCH3CH2OH
In step (iv), ethanol reacts with benzenediazonium chloride (C6H5N2Cl). Ethanol reduces the diazonium salt to benzene, while getting oxidized to ethanal.
CH3CH2OH+C6H5N2Cl→C6H6+CH3CHO+N2+HCl
The final major product (X) is benzene.
Answer: Benzene
