question_answer

Which one of the following compounds gives a positive iodoform test    [MP PMT 1997]

A)                 Pentanal             

B)                 1-phenyl ethanol

C)                 2-phenyl ethanol            

D)                 3-pentanol

Correct Answer: B

Solution :

               \[C{{H}_{3}}-CH-OH\] \[\underset{{{I}_{2}}}{\mathop{\xrightarrow{NaOH}}}\,\underset{\text{Yellow}\,\,ppt}{\mathop{CH{{I}_{3}}}}\,\]                                  Iodoform test is given by compounds in which \[C{{H}_{3}}-\underset{OH}{\mathop{\underset{|}{\mathop{CH}}\,}}\,-\] or \[C{{H}_{3}}-\underset{O}{\mathop{\underset{||}{\mathop{CH}}\,}}\,-\] group is present.