• # question_answer What is the chief product obtained when n-butane is treated with bromine in the presence of light at ${{130}^{o}}C$ [IIT-JEE 1995] A) $\underset{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{{H}_{3}}}{\mathop{\underset{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|}{\mathop{C{{H}_{3}}-C{{H}_{2}}-CH-Br}}\,}}\,$ B) $\underset{C{{H}_{3}}\,\,\,\,\,\,\,\,}{\mathop{\underset{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}{\mathop{C{{H}_{3}}-CH-C{{H}_{2}}-Br}}\,}}\,$ C) $\underset{\,\,\,\,\,\,\,\,\,C{{H}_{3}}}{\mathop{\underset{\,\,\,\,|}{\mathop{\overset{\,\,\,\,\,\,\,\,\,\,\,C{{H}_{3}}}{\mathop{\overset{\,\,\,\,\,\,|}{\mathop{C{{H}_{3}}-C-Br}}\,}}\,}}\,}}\,$ D) $C{{H}_{3}}-C{{H}_{2}}-C{{H}_{2}}-C{{H}_{2}}-Br$

$C{{H}_{3}}-C{{H}_{2}}-C{{H}_{2}}-C{{H}_{3}}+B{{r}_{2}}\underset{\,\,\,\,{{130}^{o}}C}{\mathop{\xrightarrow{\text{Light}}}}\,$$\underset{\begin{smallmatrix} \text{2}-\text{Bromo}\,\text{butane}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\text{ } \\ \,\,\,\text{(Main}\,\text{product)} \end{smallmatrix}}{\mathop{C{{H}_{3}}-\underset{\underset{Br\,\,}{\mathop{|\,\,\,\,\,}}\,}{\mathop{CH}}\,-C{{H}_{2}}-C{{H}_{3}}}}\,+\underset{\begin{smallmatrix} \text{1}-\text{Bromo}\,\text{butane} \\ \,\,\,\,\,\,\,\,\,\,\,\text{(Minor)} \end{smallmatrix}}{\mathop{C{{H}_{3}}-C{{H}_{2}}-C{{H}_{2}}-C{{H}_{2}}-Br}}\,$ 2-Bromobutane is the main product because ${{2}^{o}}$carbonium ion is more stable than ${{1}^{o}}$.