Oxidants distinguishing HCOOH from CH3COOH by further oxidation

Steps:

• Strong oxidants convert CH3CH2OH to CH3COOH and HCOOH to CO2 + H2O.
• These oxidants stop at CH3COOH, so no reaction with it.
• Reagents reacting differently: oxidize HCOOH (e.g., decolorize) but not CH3COOH.
• Evaluate options for this selective oxidation behavior.

Why C is correct:

• Dilute acidified KMnO4 oxidizes HCOOH to CO2 (purple to colorless) but CH3COOH resists oxidation, per standard organic redox.

Why the others are wrong:

• A: Both HCOOH and CH3COOH react with Na2CO3(aq) to evolve CO2 gas equally.
• B: Fehling's reagent tests aldehydes/reductants but does not oxidize ethanol to ethanoic acid.

Final answer: C