$(i)$ Hinsberg test
$(ii)$ Carbyl amine test
$(iii)$ Hofmann mustard oil test
$(iv)$ $HNO_2$ test

${{C}_{2}}{{H}_{5}}N{{H}_{2}} \xrightarrow{HN{{O}_{2}}}A \xrightarrow{PC{{l}_{5}}}B \xrightarrow{H.N{{H}_{2}}}C$


$\begin{array}{*{20}{c}}
O \\
{||} \\
{C{H_3} - C - N{H_2}}
\end{array}$ $\xrightarrow{{KOBr}}$ $(A)$
$\begin{array}{*{20}{c}}
O \\
{||} \\
{C{H_3} - C - N{H_2}}
\end{array}$ $\xrightarrow{{LiAlH_4}}$ $(B)$