$(II)\,\,\,{{H}_{2}}C=CH-C{{H}_{2}}-\overset{+}{\mathop{C}}\,H-C{{H}_{3}}$

$(III)\,\,\,\begin{matrix}
   \,\,\,\,\,C{{H}_{3}}\,  \\
   |\,  \\
   {{H}_{3}}C-C-\overset{+}{\mathop{C}}\,{{H}_{2}}  \\
   |\,  \\
   \,\,\,C{{H}_{3}}  \\
\end{matrix}$

$(i)$ ${C_6}{H_5}{N^ + } \equiv NC{l^ - }$ $(ii)$ ${C_6}{H_5}{N^ + } \equiv N$
$(iii)$ ${{\overset{\centerdot }{\mathop{C}}\,}_{6}}{{H}_{5}}$ $(iv)$ $C_6H_5Cl$

$(I)$ $CH_2 = CH - C \equiv CH$

$(II)$ $CH \equiv C - C\equiv  CH$

$(III)$ $CH_3 - CH =  CH_2$

$(IV) $ $CH_2 = CH - C =  CH_2$