question_answer

Which of the following compounds is not formed in iodoform reaction of acetone?

A)  \[C{{H}_{3}}COC{{H}_{2}}I\]      

B)  \[IC{{H}_{2}}COC{{H}_{2}}I\]

C)  \[C{{H}_{3}}COCH{{I}_{2}}\]      

D)  \[C{{H}_{3}}COC{{I}_{3}}\]

Correct Answer: B

Solution :

                 Mechanism of iodoform reaction takes place  by two steps (i) lodonation of \[-\overset{O}{\mathop{\overset{|\,\,|}{\mathop{C}}\,}}\,-C{{H}_{3}}\]group to form\[-\overset{O}{\mathop{\overset{|\,\,|}{\mathop{C}}\,}}\,-C{{I}_{3}}\] \[C{{H}_{3}}-\overset{O}{\mathop{\overset{|\,\,|}{\mathop{C}}\,}}\,-C{{H}_{3}}\xrightarrow{O{{I}^{-}}}C{{H}_{3}}-\overset{O}{\mathop{\overset{|\,\,|}{\mathop{C}}\,}}\,-C{{H}_{2}}I+O{{H}^{-}}\] \[C{{H}_{3}}-\overset{O}{\mathop{\overset{|\,\,|}{\mathop{C}}\,}}\,-C{{H}_{2}}I\xrightarrow{O{{I}^{-}}}C{{H}_{3}}-\overset{O}{\mathop{\overset{|\,\,|}{\mathop{C}}\,}}\,-CH{{I}_{2}}+O{{H}^{-}}\]\[C{{H}_{3}}-\overset{O}{\mathop{\overset{|\,\,|}{\mathop{C}}\,}}\,-CH{{I}_{2}}\xrightarrow{O{{I}^{-}}}C{{H}_{3}}-\overset{O}{\mathop{\overset{|\,\,|}{\mathop{C}}\,}}\,-C{{I}_{3}}+O{{H}^{-}}\] (ii) Elimination of \[-C{{I}_{3}}\]as: \[C{{I}_{3}}\]anion