question_answer 75)

  An aromatic compound 'A' (Molecular formula ) gives positive 2,4-DNP test. It gives a yellow precipitate of compound 'B' on treatment with iodine and sodium hydroxide solution. Compound ?A? does not give Tollen's or Fehling's test. On drastic oxidation with potassium permanganate it form a carboxylic acid 'C' (Molecular formula ), which is also formed along with the yellow compound in the above reaction. Identify A, B and C and write all the reactions involved.

Answer:

                  Since aromatic compound 'A' (MF ) gives positive 2, 4-DNP test, it must be an aldehyde or a  ketone. (ii) Since compound 'A' does not give Tollens' test or Fehling?s test, therefore, 'A' must be a ketone. (iii) Since compound 'A' on treatment with , gives yellow ppt. of compound 'B', therefore, compound ?B? must be iodoform and the ketone 'A' must be a methyl ketone. (iv) Since methyl ketone 'A' on drastic oxidation with KMn04 gives a carboxylic acid 'C'therefore, 'C' must be benzole acid and compound 'A' must be acetophenone (v) If 'A' is acetophenone, then all the reactions described above may be explained as follows