Write short notes on the following:
$(i)$ Carbylamine reaction
$(ii)$ Diazotisation
$(iii)$ Hofmann's bromamide reaction
$(iv)$ Coupling reaction
$(v)$ Ammonolysis
$(vi)$ Acetylation
$(vii)$ Gabriel phthalimide synthesis.

(N/A) $(i)$ Carbylamine reaction: Used to identify primary amines. Aliphatic and aromatic primary amines react with chloroform and ethanolic $KOH$ to form isocyanides (carbylamines) with unpleasant odors.
$R-NH_2 + CHCl_3 + 3KOH(alc.) \xrightarrow{\Delta} R-NC + 3KCl + 3H_2O$
$(ii)$ Diazotisation: Aromatic primary amines react with nitrous acid $(NaNO_2 + HCl)$ at $273-278 \ K$ to form diazonium salts.
$(iii)$ Hofmann bromamide reaction: Amides react with $Br_2$ and $NaOH$ to produce a primary amine with one carbon atom less.
$R-CONH_2 + Br_2 + 4NaOH \to R-NH_2 + Na_2CO_3 + 2NaBr + 2H_2O$
$(iv)$ Coupling reaction: Arenediazonium salts react with phenol or aromatic amines to form colored azo compounds via electrophilic substitution.
$(v)$ Ammonolysis: Alkyl halides react with ethanolic ammonia to form amines via nucleophilic substitution,often resulting in a mixture of $1^o, 2^o, 3^o$ amines and quaternary salts.
$(vi)$ Acetylation: Introduction of an acetyl group into primary or secondary amines using acid chlorides or anhydrides to form amides.
$(vii)$ Gabriel phthalimide synthesis: $A$ method to prepare aliphatic primary amines by treating phthalimide with $KOH$,followed by alkyl halide and alkaline hydrolysis.