Anorganic compound (A) having molecular formula `C_9H_10O` forms an orange red precipitate (B) with 2,4-DNP reagent. Compound (A) gives a yellow precipitate (C) When heated in the presence of iodine and NaOH alongwith a colourless compound (D). (A) does not reduce Tollens' reagent or Fehling solution nor does it decolourise bromine water. On drastic oxidation of (A) with chromic acid, a carboxylic acid (E) of molecular formula `C_7H_6O_2` is formed. Deduce the structures of the organic compounds (A) to (E ).

Explanation

(i) Positive test with 2,4 DNP and negtive tests with Tollen's reagent and Fehling solution suggest that the compound [A] is a ketone. Since it responds to iodoform test `(I_(2)//NaOH)`, it must be a methyl ketone `(CH_(3)COR)`.
(ii) The molecular formula suggests a high degree pf unsaturation which is ruled out because it does not decolourise either bromine water or Baeyer's reagent. Thus, we many conclude that it is an aromatic compound and the side chain has `-COCH_(3)` group .
Thus, the compound [A] is `C_(6)H_(5)CH_(2)COCH_(3)` (I-Phenylpropanone).
The reaction involved are as follows: