${H_2}C = CHC{H_2}Br\xrightarrow{{NaCN}}Y\xrightarrow[{2.\,{H_3}{O^ + }}]{\begin{subarray}{l}
1.{C_6}{H_5}MgBr\, \\
diethylether
\end{subarray} }Z$
${CH}_{4}+{I}_{2} \underset{\text { Reversible }}{\stackrel{{hv}}{\longrightarrow}} {CH}_{3}-{I}+{HI}$