$C{{H}_{3}}\,-\,\,\overset{\overset{C{{H}_{3}}}{\mathop{|}}\,}{\mathop{C}}\,H\,\,-\,\,C{{H}_{3}}(excess)\,\,+\,\,B{{r}_{2}}\,\xrightarrow{hv}$
$\,\,\,\,C{{H}_{3}}\,-\,\,\overset{\overset{C{{H}_{3}}}{\mathop{|}}\,}{\mathop{\underset{\underset{Br}{\mathop{|}}\,}{\mathop{C}}\,}}\,\,\,-\,\,C{{H}_{3}}\,+\,\,C{{H}_{3}}\,-\,\,CH\,\,-\,\,C{{H}_{2}}\,-\,\,Br$
$reagent$ શું હશે?