What happens when aniline is i) treated with benzene diazonium chloride. [1] ii) heated with chloroform in presence of alc. KOH . [1]

i) When aniline is treated with benzene diazonium chloride, it undergoes an azo coupling reaction to form p-aminoazobenzene (an azo dye). The reaction occurs under weakly acidic conditions (pH ~4–5) and involves the electrophilic substitution of the diazonium ion onto the electron-rich benzene ring of aniline. The product is an orange-red dye, commonly used in textiles and indicators.

anilineaniline+C₆H₅N₂+ Cl^-weakly acidic (pH 4–5)p-Aminoazobenzenep-Aminoazobenzene

{"type":"reaction","reactants":[{"name":"aniline"},{"formula":"C6H5N2+ Cl-"}],"products":[{"formula":"C6H5N=NC6H4NH2"}],"conditions":"weakly acidic (pH 4–5)","caption":"Azo coupling of aniline with benzene diazonium chloride"}

ii) When aniline is heated with chloroform in the presence of alcoholic KOH, it undergoes the Carbylamine reaction, producing phenyl isocyanide (phenyl carbylamine). This reaction is a test for primary amines (positive result: foul-smelling isocyanide). The mechanism involves deprotonation of chloroform by KOH, followed by nucleophilic attack by the amine and rearrangement.

anilineaniline+chloroformchloroform+KOHheatPhenyl isocyanide (phenyl carbylamine)Phenyl isocyanide (phenyl carbylamine)

{"type":"reaction","reactants":[{"name":"aniline"},{"formula":"CHCl3"},{"formula":"KOH (alc.)"}],"products":[{"formula":"C6H5NC"}],"conditions":"heat","caption":"Carbylamine reaction of aniline"}