question_answer 1)

  Write hydrocarbon radicals that can be formed as intermediates during mono chlorination of 2-methyl-propane? Which of them is more stable? Give reasons.

Answer:

  \[C{{H}_{3}}-\underset{\underset{\underset{2-Methylpropane}{\mathop{\text{C}{{\text{H}}_{\text{3}}}}}\,}{\mathop{|}}\,}{\mathop{CH}}\,-C{{H}_{3}}\xrightarrow[(Monochlorination)]{C{{l}_{2}},hv}\] \[C{{H}_{3}}-\underset{\underset{\underset{I({{3}^{o}}radical)}{\mathop{\text{C}{{\text{H}}_{\text{3}}}}}\,}{\mathop{|}}\,}{\mathop{\overset{\centerdot }{\mathop{C}}\,}}\,-C{{H}_{3}}+C{{H}_{3}}-\underset{\begin{smallmatrix}  | \\  \underset{II({{1}^{o}}radical)}{\mathop{C{{H}_{3}}}}\, \end{smallmatrix}}{\mathop{CH}}\,-\overset{\centerdot }{\mathop{C}}\,{{H}_{2}}\] Intermediate hydrocarbon radical \[I\] (having nine \[\alpha \]-hydrogen atoms) is tertiary whereas radical \[II\] (having only one \[\alpha \]-hydrogen atom) is primary. Radical \[I\] is more stable due to hyper conjugation.