\(C{H_3}\, - \,\,C\, \equiv \,CH\,\,\xrightarrow{{HBr}}\,\,C{H_3}\, - \,\,\mathop {\mathop C\limits_{\mathop |\limits_{Br} } }\limits^{\mathop |\limits^{Br} } \,\, - \,\,C{H_3}\)
${C_7}{H_8}\xrightarrow[\Delta ]{{3C{l_2}}}A\xrightarrow{{B{r_2}/Fe}}B\xrightarrow{{Zn/HCl}}C$