Question

An organic compound (A) having molecular formula C9H10O forms orange red ppt (B) with 2,4-DNP reagent. Compound (A) gives yellow ppt (C) when heated in the presence of iodine and NaOH along with a colourless compund (D). (A) does not reduce Tollen's reagent or Fehling's solution nor does it decolourise the Br2 water. On drastic oxidation of (A) with chromic acid, carboxylic acid (E) of molecular formula C7H6O2 is formed. Deduce the structure of the organic compounds (A) to (E). (From School test paper).Please answer!

Answer 1

(1) It is Carbonyl compounds as it give 2,4-DNP test.
(2)It should be ketones as it does not reduce fehling solution and tollens reagent.
(3)It should be methtyl ketones as it give iodoform test.
This shows it has a carbonyl group which is not an aldehyde (that means it is a ketone) and it is a methyl ketone (give iodoform test).

Answer 2

Hey !!

(a) It is an aldehyde or ketone as it forms 2,4 - DNP derivative.

(b) As the compound reduced Tollen's reagent and undergoes Cannizzaro reaction, it is an aldehyde and not a ketone.

(c) On vigrous oxidation, it gives 1,2 - benzenedicarboxylic acid. So, it must have an alkyl group at o-ortho position with respect to CHO group on the benzene ring.

(d) Molecular formula suggests that it should be 2-ethyl benzaldehyde .

Good luck !!