$\begin{array}{*{20}{c}}
  {C{H_3}C{H_2}CH - C{H_2}} \\ 
  {\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|} \\ 
  {\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,Br\,\,\,\,\,\,\,\,\,Br\,\,} 
\end{array}\xrightarrow[\begin{subarray}{l} 
  (ii)\,NaN{H_2} \\ 
  in\,liq.\,N{H_3} 
\end{subarray} ]{{(i)\,KOH\,alc.}}$