Carboxylic acids: past paper questions

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• Question 19May/June 2026, paper 11Multiple choice1 mark

  Which ion is present in dilute aqueous propanoic acid?

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• Question 35Oct/Nov 2025, paper 11Multiple choice1 mark

  Which statement about carboxylic acids is correct?

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• Question 19Oct/Nov 2024, paper 11Multiple choice1 markHas a diagram

  An organic compound, X, has a molecular formula ${\text{C}}_4{\text{H}}_8{\text{O}}_2$ and turns damp blue litmus paper red. What is the displayed formula of X?

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• Question 8Oct/Nov 2023, paper 21Structured7 marks

  Ethanoic acid is manufactured from methanol. $${\mathrm{C}\mathrm{H}}_3\mathrm{O}\mathrm{H}(\mathrm{g})+\mathrm{C}\mathrm{O}(\mathrm{g})\rightleftharpoons {\mathrm{C}\mathrm{H}}_3\mathrm{C}\mathrm{O}\mathrm{O}\mathrm{H}(\mathrm{g})$$ The forward reaction is exothermic.

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• Question 31May/June 2026, paper 11Multiple choice1 mark

  The structural formulae of three compounds are listed. 1 ${\text{CH}}_3\text{COOH}$ 2 ${\text{HCOOCH}}_3$ 3 ${\text{CH}}_3{\text{CH}}_2\text{OH}$ Which compounds are carboxylic acids?

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• Question 8Oct/Nov 2025, paper 12Multiple choice1 mark

  Which structure shows the carboxylic acid with the lowest relative molecular mass?

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• Question 35Oct/Nov 2024, paper 11Multiple choice1 markHas a diagram

  Two reactions are shown.

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• Question 8Oct/Nov 2023, paper 22Structured7 marks

  The equation for the reaction of carbon monoxide with hydrogen at a high temperature in a closed container is shown. $$\mathrm{C}\mathrm{O}(\mathrm{g})+2{\mathrm{H}}_2(\mathrm{g})\rightleftharpoons {\mathrm{C}\mathrm{H}}_3\mathrm{O}\mathrm{H}(\mathrm{g})$$ methanol The forward reaction is exothermic.

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• Question 35May/June 2026, paper 11Multiple choice1 markHas a diagram

  The displayed formula of an ester is shown. Which acid and which alcohol react to form this ester?

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• Question 32Oct/Nov 2025, paper 12Multiple choice1 mark

  Which two compounds react together to form ${\text{CH}}_3{\text{CH}}_2{\text{COOCH}}_3$?

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• Question 34Oct/Nov 2024, paper 12Multiple choice1 mark

  How many different unbranched esters have the molecular formula ${\text{C}}_4{\text{H}}_8{\text{O}}_2$?

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• Question 38May/June 2023, paper 11Multiple choice1 mark

  An organic compound, P, is dissolved in water. The concentration of the solution is $0.1\text{ mol}\mathrm{/}{\text{dm}}^3$ and the pH is 3.

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• Question 35May/June 2026, paper 12Multiple choice1 mark

  Ethanol can be converted by bacteria into vinegar, which contains ethanoic acid. Which type of chemical reaction is caused by the bacteria?

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• Question 35Oct/Nov 2025, paper 12Multiple choice1 mark

  Copper(II) oxide reacts with dilute ethanoic acid. Which equation for this reaction is correct?

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• Question 37Oct/Nov 2024, paper 12Multiple choice1 mark

  Two statements are shown. 1 When ethanol is made from glucose by fermentation, each glucose molecule produces two molecules of ethanol. 2 When ethanoic acid is made from ethanol, the ethanol acts as a reducing agent.

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• Question 34May/June 2023, paper 12Multiple choice1 mark

  What is the structural formula of propyl methanoate?

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• Question 36May/June 2026, paper 12Multiple choice1 mark

  An ester has the formula ${\text{C}}_2{\text{H}}_5{\text{COOC}}_2{\text{H}}_5$. Which pair of compounds would react together to form this ester?

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• Question 1Oct/Nov 2025, paper 22Structured6 marks

  Choose from the following compounds to answer the questions.

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• Question 7Oct/Nov 2024, paper 21Structured14 marksHas a diagram

  Propanoic acid can be represented by the formula ${\text{CH}}_3{\text{CH}}_2\text{COOH}$. Propanoic acid reacts with methanol, ${\text{CH}}_3\text{OH}$, to produce an ester. Name the ester formed and draw its displayed formula.

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• Question 37May/June 2023, paper 12Multiple choice1 markHas a diagram

  The structure of an ester is shown. Which two compounds react to form this ester?

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• Question 8May/June 2026, paper 21Structured9 marks

  This question is about alcohols. Describe the manufacture of ethanol from ethene.

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• Question 8Oct/Nov 2025, paper 22Structured9 marksHas a diagram

  Fig. 8.1 shows the displayed formula of an unsaturated carboxylic acid, X. Explain why X is unsaturated.

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• Question 7Oct/Nov 2024, paper 22Structured14 marksHas a diagram

  Esters are represented by the formula ${\mathrm{C}}_n{\mathrm{H}}_{2n}{\mathrm{O}}_2$. State the name given to a formula such as ${\mathrm{C}}_n{\mathrm{H}}_{2n}{\mathrm{O}}_2$.

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• Question 8May/June 2026, paper 22Structured9 marks

  This question is about carboxylic acids. Vinegar is an aqueous solution containing ethanoic acid. During the production of vinegar, ethanoic acid is formed from ethanol.

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• Question 33May/June 2025, paper 11Multiple choice1 mark

  An ester has the structural formula $\mathrm{C}{\mathrm{H}}_3\mathrm{C}\mathrm{O}\mathrm{O}\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_3$. What is the name of this ester?

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• Question 8May/June 2024, paper 21Structured9 marksHas a diagram

  Fig. 8.1 is a flow diagram showing information about some organic chemical reactions.

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• Question 36May/June 2025, paper 12Multiple choice1 markHas a diagram

  The diagram shows the structure of a compound called ethanoic anhydride. $1\text{ mol}$ of ethanoic anhydride reacts with water to form $2\text{ mol}$ of a carboxylic acid only. This carboxylic acid reacts with ethanol to form an ester.

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• Question 8May/June 2025, paper 21Structured11 marksHas a diagram

  Fig. 8.1 shows the displayed formula of methylbut-2-enoate. Fig. 8.1 Methylbut-2-enoate is an unsaturated ester. Explain why methylbut-2-enoate is unsaturated.

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• Question 4May/June 2025, paper 22Structured13 marks

  Ethanoic acid, ${\mathrm{C}\mathrm{H}}_3\mathrm{C}\mathrm{O}\mathrm{O}\mathrm{H}$, is a member of the homologous series of carboxylic acids. Give the general formula of the homologous series of carboxylic acids.

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