question_answer

An organic compound [A] with molecular formula \[{{\text{C}}_{8}}{{H}_{8}}O\]forms an orange red precipitate with 2, 4-DNP reagent and gives yellow precipitate on heating with iodine in the presence of sodium hydroxide. It neither reduces Tollens reagent or Fehlings reagent, nor decolourises bromine water or Baeyers reagent. Compound A is

A)  

B)  

C)  

D)  

Correct Answer: D

Solution :

 Compound A forms 2, 4-DNP derivative Therefore, it is an aldehyde or a ketone. Since, it does not reduce Tollens or Fehling reagent, [A] must be ketone. [A] responds to iodoform test Therefore, it should be a methyl ketone. The molecular formula of A indicates high degree of unsaturation, yet it does not decolourise bromine water or Baeyer reagent. This indicates the presence of unsaturation due to an aromatic ring. The molecular formula of  indicates that it should be a phenyl methyl, ketone, i.e., acetophenone.