Functional isomers: $\mathop {C{H_3}C{H_2}C{H_2} - C{H_2} - OH}\limits_{{\text{Butanol}}} $ and $\mathop {{C_2}{H_5} - O - {C_2}{H_5}}\limits_{{\text{Diethyl}}\,{\text{ether}}} $
Metamers: $C{H_3}C{H_2}C{H_2}COOH\,({C_4}{H_8}{O_2})$ and $\mathop {C{H_3} - O - {C_3}{H_7}}\limits_{{\text{Methyl propyl ether}}} $
$\begin{array}{*{20}{c}} A \\ {{\text{(simplest optically active alkene)}}} \end{array}\,\xrightarrow[{(ii)\,{X_2}/\Delta }]{{(i)\,{H_2}/Ni/\Delta }}$