An aromatic compound ‘A’ with molecular formula C8H8O gives positive 2,4-DNP test. It gives yellow precipitate of compound ‘B’ on treatment with sodium hypoiodite. Compound ‘A’ does not react with Tollen’s or Fehling’s reagent; on drastic oxidation with KMnO4 it forms a carboxylic acid ‘C’. Elucidate the structures of A, B, and C. Also give their IUPAC names.
An aromatic compound ‘A’ with molecular formula C8H8O gives positive 2,4-DNP test. It gives yellow precipitate of compound ‘B’ on treatment with sodium hypoiodite. Compound ‘A’ does not react with Tollen’s or Fehling’s reagent; on drastic oxidation with KMnO4 it forms a carboxylic acid ‘C’. Elucidate the structures of A, B, and C. Also give their IUPAC names.
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Solution and Explanation
Compound A: Compound A is an aromatic ketone, phenyl methyl ketone (acetophenone), as it gives a positive 2,4-DNP test and does not respond to Tollen’s or Fehling’s reagents.
IUPAC Name: 1-phenylethanone
Compound B: Compound B is benzene with a carboxylic acid group (benzoic acid), formed on oxidation of acetophenone. Compound A reacts with NaOI (iodoform test) to form compound B, which is a yellow precipitate of iodoform. This confirms the methyl ketone group.
IUPAC Name: triiodomethane (Iodoform)
Compound C: Compound C is benzoic acid, formed upon drastic oxidation of acetophenone with KMnO4.
IUPAC Name: benzenecarboxylic acid
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