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An aromatic compound 'A' (Molecular form...

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 potassium 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.

Text Solution

Verified by Experts

(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
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Knowledge Check

  • An aromatic compound (X) (C_(8)H_(8)O) gives positive 2, 4-DNP test. It gives a yellow precipitate of compound (Y) on reaction with iodine and sodium hydroxide solution. (X) does not give Tollens' test on oxidation under drastic conditions. It gives a carboxylic acid (Z) (C_(7)H_(6)O_(2)) .(Z) is also formed with (Y) during the reaction. (X), (Y) and (Z) respectively are

    A
    `C_(6)H_(5)COCH_(3), CHI_(3), C_(6)H_(5)COOH`
    B
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    C
    `C_(6)H_(5)COCH_(3), CHI_(3), CH_(3)COOH`
    D
    `CH_(3)CHO,CHI_(3), C_(6)H_(5)COOH`
  • A compound with molecular formula, C_(4)H_(8)O gives a positive haloform test and a 2, 4-DNP derivative. The compound is

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    B
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    C
    `(CH_(3))_(2)CHCHO`
    D
    All the above
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    A
    B
    `C_(6)H_(5)CHOHCH_(3)`
    C
    D
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