Formation of Ethanoic Acid
Chemistry: Cambridge International GCSE Supplement, topic 11.7.4
Formation of Ethanoic Acid
Ethanoic acid is formed by oxidising ethanol using acidified potassium manganate(VII) and by bacteria in vinegar production.
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What is ethanoic acid?
- Ethanoic acid is a simple carboxylic acid with the formula CH3COOH.
- It is also called vinegar acid.
- Ethanoic acid forms naturally and in labs from ethanol oxidation.
Oxidation of ethanol using acidified potassium manganate(VII)
- Ethanol (CH3CH2OH) reacts with acidified potassium manganate(VII) to form ethanoic acid.
- The purple potassium manganate(VII) solution turns colourless or brown as it oxidises ethanol.
- The overall reaction: ethanol + acidified KMnO4 → ethanoic acid + water.
Oxidation reaction details
- Potassium manganate(VII) supplies oxygen atoms for oxidation.
- Ethanol's -OH group is converted to a -COOH group, forming ethanoic acid.
- This is a common method to make carboxylic acids.
Bacterial oxidation in vinegar production
- Vinegar production uses bacteria to oxidise ethanol to ethanoic acid naturally.
- Bacteria convert ethanol to ethanoic acid by adding oxygen from the air slowly.
- This biological oxidation is slower and produces vinegar with a distinctive taste.
Comparing chemical and bacterial oxidation
- Chemical oxidation uses acidified KMnO4 for a fast reaction.
- Bacterial oxidation happens naturally and is slower, used in food chemistry.
- Both methods convert ethanol to ethanoic acid thoroughly.
Test yourself on Formation of Ethanoic Acid
Which substance is used as an oxidising agent to convert ethanol to ethanoic acid in a laboratory setting?