\((B)\) Hoffmann bromamide reaction \(\rightarrow\) known reaction of isocynates

\(R - CO - NH _{2}+ X _{2}+4 NaOH \rightarrow R - NH _{2}+\)

\(2 NaX + Na _{2} CO _{3}+2 H _{2} O\)

Intermediate : \(R - N = C = O\) (isocyanate)

\((C)\) Carbylamine reaction \(\rightarrow\) Test for primary amine

\(R - NH _{2}\) or \(Ar - NH _{2}+ CHCl _{3}+3 KOH \rightarrow RNC\) or \(Ar - NC +3 KCl +3 H _{2} O\)

\((D)\) Hoffmann orientation \(\rightarrow\) Anti saytzeff (Formation of less substituted alkene as major product)