Q.Write short notes on the following:
i. Hofmann's bromamide reaction
ii. Ammonolysis
iii. Gabriel phthalimide synthesis
iv. Schotten-Baumann reaction
v. Carbylamine reaction
vi. Mustard oil reaction
vii. Coupling reaction
viii. Diazotisation
ix. Gomberg reaction

Step 1. i. HOFMANN'S BROMAMIDE REACTION: a primary amide (R-CO-NH2) + Br2 in aqueous/ethanolic KOH gives a primary amine (R-NH2) with ONE CARBON FEWER, + K2CO3 + KBr + H2O.

Step 2. ii. AMMONOLYSIS: an alkyl (or benzyl) halide heated with alcoholic ammonia in a sealed tube gives a mixture of 1/2/3 degree amines and a quaternary ammonium salt, via successive nucleophilic substitution (excess NH3 favours the primary amine; excess halide favours the quaternary salt).

Step 3. iii. GABRIEL PHTHALIMIDE SYNTHESIS: phthalimide + ethanolic KOH gives potassium phthalimide, which + an alkyl halide (SN2) gives N-alkylphthalimide, hydrolysed (aqueous KOH) to release a PURE primary amine -- this route cannot make an aromatic amine like aniline, since aryl halides resist the SN2 step.

Step 4. iv. SCHOTTEN-BAUMANN REACTION: an aromatic amine (e.g. aniline) + an acid chloride (e.g. benzoyl chloride), in the presence of NaOH, gives the corresponding anilide (N-phenylbenzamide) -- a nucleophilic acyl substitution at nitrogen.

Step 5. v. CARBYLAMINE REACTION: a primary amine (aliphatic or aromatic) + CHCl3/alcoholic KOH gives a foul-smelling isocyanide (carbylamine); used as a test to identify primary amines, since secondary/tertiary amines give no such reaction.

Step 6. vi. MUSTARD OIL REACTION: a primary amine + CS2 gives an N-alkyldithiocarbamic acid, which with HgCl2 gives an alkyl isothiocyanate (mustard-oil smell) -- another primary-amine identification test. …

For each named reaction, state its exact reagent set, the class of starting material it needs, and its defining product -- the reagent set is what distinguishes closely related named reactions (e.g. carbyl …

• Mixing up the carbylamine reaction (CHCl3/KOH, gives an isocyanide) with the mustard oil reaction (CS2 then HgCl2, gives an isothiocyanate) -- both are primary-amine identification tests with an unpleasant-s …