Why is the conversion of ethanol to ethanoic acid an oxidation reaction ? Name the oxidising agent used in this conversion. Write chemical equation for this oxidation reaction. How is this reaction different from the reaction in which ethanol burns in the presence of oxygen ?
Generated by claude-sonnet-4-6 · 2026-06-15 06:47 · grounding rag
Model Answer
Oxidation: In the conversion of ethanol (C₂H₅OH) to ethanoic acid (CH₃COOH), oxygen is added to ethanol. Since the reaction involves addition of oxygen to the starting material, it is called an oxidation reaction.
Oxidising agent: Alkaline potassium permanganate (KMnO₄) or acidified potassium dichromate (K₂Cr₂O₇).
Chemical equation:
$$\text{CH}_3\text{CH}_2\text{OH} \xrightarrow{[\text{O}] \text{ Alkaline KMnO}_4} \text{CH}_3\text{COOH}$$
Difference from burning: When ethanol burns in oxygen, it undergoes complete oxidation producing CO₂ and water with release of energy. The oxidation of ethanol to ethanoic acid is controlled/partial oxidation where ethanol is converted to a carboxylic acid, not CO₂ and water.
Source: Chapter 4, Section 4.3.2 Oxidation
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Explanation
- Examiners expect three distinct parts: reason for oxidation, name of oxidising agent, balanced/arrow equation, and the difference from combustion.
- "Addition of oxygen = oxidation" is the key concept from Section 4.3.2.
- Both oxidising agents (KMnO₄ and K₂Cr₂O₇) are acceptable; mention either or both.
- The key difference: combustion is complete oxidation → CO₂ + H₂O; this reaction is partial/controlled oxidation → CH₃COOH.