Propan-1-ol can be oxidised to form propanoic acid. Describe what happens during this oxidation reaction and explain why propanoic acid is classified as an organic acid.

Cambridge International IGCSE Chemistry (0620) — 11.6 Alcohols · Describe and Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Propan‑1‑ol is oxidised by an oxidising agent such as acidified potassium dichromate or potassium permanganate. The –OH group of the alcohol is converted to a –COOH group, giving propanoic acid.

Propanoic acid contains a carboxyl (–COOH) functional group. In water the –COOH group donates a proton, releasing H⁺ ions. The release of H⁺ makes the solution acidic, so propanoic acid is classified as an organic acid.

Examiner tips

  • Use the exact terms – oxidising agent, –COOH, proton donor; show the conversion of –OH to –COOH; explain H⁺ release to justify acidity.

Common mistakes

  • Confusing the oxidising agent with a reducing agent; not specifying the –COOH group; failing to mention proton donation or H⁺ release.

Mark scheme (4 marks)

  1. Propan-1-ol is oxidised by/reacts with an oxidising agent (e.g. acidified potassium manganate(VII) or potassium dichromate(VI))
  2. The –OH group is converted / the alcohol functional group changes to a –COOH (carboxyl/carboxylic acid) group
  3. Propanoic acid contains a –COOH (carboxylic acid) functional group
  4. Propanoic acid dissolves in / reacts with water to release / produce hydrogen ions (H⁺) / acts as a proton donor, making the solution acidic

Key terms in this question

oxidation

Related

More Alcohols questions

▶ Try answering this question with AI marking (free) →