Ethanol can be oxidised to form a carboxylic acid. Describe the properties of carboxylic acids, including their functional group, their behaviour as acids, and name the carboxylic acid produced when ethanol is oxidised.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Alcohols are a homologous series of organic compounds that can be oxidised to form carboxylic acids. Carboxylic acids are widely used in food preservation and industrial processes.
Model answer (5 marks)
Carboxylic acids contain the functional group –COOH.
They are acidic, donating a proton to give the carboxylate ion.
They react with metals, carbonates and bases – e.g. with NaOH to give the sodium salt.
They form a homologous series: methanoic acid, ethanoic acid, propanoic acid, butanoic acid (and so on).
Ethanol oxidises to ethanoic acid.
They are acidic, donating a proton to give the carboxylate ion.
They react with metals, carbonates and bases – e.g. with NaOH to give the sodium salt.
They form a homologous series: methanoic acid, ethanoic acid, propanoic acid, butanoic acid (and so on).
Ethanol oxidises to ethanoic acid.
Examiner tips
- Use the exact term –COOH and ethanoic acid. Show acidic behaviour with a reaction. Mention the homologous series. Keep answer concise to fit 5 marks.
Common mistakes
- Writing ‘acetic acid’ instead of ethanoic acid. Omitting the –COOH functional group. Failing to give an example of acidic reaction.
Mark scheme (5 marks)
- Carboxylic acids contain the functional group –COOH
- The carboxylic acid produced when ethanol is oxidised is ethanoic acid
- Carboxylic acids are acidic / have typical acidic properties
- Carboxylic acids react with metals / carbonates / bases (any one correct example of acidic behaviour)
- Carboxylic acids belong to a homologous series; the first four members are methanoic acid, ethanoic acid, propanoic acid and butanoic acid (any correct additional member named beyond ethanoic acid, or correct identification of the series)
Key terms in this question
carboxylic acids · functional group · oxidised
Related
- All OCR A-Level Chemistry B: Salters (H433) revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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