An aromatic compound 'A' (molecular formula C_(8)H_(8)O) 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 potessium permanganate it forms a carboxylic acid 'C' (Molecular formula C_(7)H_(6)O_(2)), which is also formed along with the yellow compound in the above reaction. identify A,B and C and write all the reactions involved.

An aromatic compound 'A' (molecular formula C_(8)H_(8)O) gives positiv

1.	An aromatic compound 'A' (molecular formula C_(8)H_(8)O) 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 potessium permanganate it forms a carboxylic acid 'C' (Molecular formula C_(7)H_(6)O_(2)), 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» Solution :(i) Since aromatic compound 'A' (MF `C_(8)H_(8)O`) gives positive 2,4-DNP test, it MUST be an ALDEHYE 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 treatement with `I_(2)//NaOH`, 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 `KMnO_(4)` gives a carboxylic acid 'C' (MF `C_(7)H_(6)O_(2)`), therefore, 'C' must be benzoic acid and compound 'A" must be acetophenone `(C_(6)H_(5)COCH_(3))` (v) If 'A' is acetophenone, then all the reactions described above may be explained as follows