Describe carbylamine reaction giving the relevant chemical equation. 

Identify $\mathrm{A}$ and $\mathrm{B}$ in the following reaction: 

Identify $\mathrm{A}$ and $\mathrm{B}$ in the following reaction:

${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{NO}}_2\stackrel{{\mathrm{Br}}_2/ {\mathrm{Fe}}^{3+}}{\to } \mathrm{A} \stackrel{{\mathrm{HNO}}_2}{\to } \mathrm{B}$

Identify $\mathrm{A}$ and $\mathrm{B}$ in the following reaction: 

${\mathrm{CH}}_3\mathrm{CN}\stackrel{{\mathrm{H}}^{+}, {\mathrm{H}}_2\mathrm{O}}{\to } \mathrm{A} \stackrel{{\mathrm{NH}}_3}{\to } \mathrm{B}$

Complete the following reaction:

${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{NH}}_2+{\mathrm{CHCl}}_3+\mathrm{alc}. \mathrm{KOH}\to$