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Aldehydes and ketones: WJEC A‑Level Chemistry questions

Every WJEC A-Level Chemistry exam question on 4.4 Aldehydes and ketones, 2016–2025, with its mark scheme and examiner’s report.

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1,204 questions

  1. Q2(a)

    Summer 2025 · Unit 4

    1 mark4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2025 Unit 4, question 2(a): State what is seen, if anything, when propan-2-ol reacts with an alkaline solution of iodine. [1]

  2. Q7(c)

    Summer 2025 · Unit 4

    3 marks4.5 Carboxylic acids and their derivatives4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2025 Unit 4, question 7(c): Each of the four compounds whose formulae are shown below are isomers. Compound Formula O R C OCH3 O H3C C S OH O CH3O C T H O HO C U CH3 Select the compound th

  3. Q8(a)(iii)

    Summer 2024 · Unit 4

    4 marks4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2024 Unit 4, question 8(a)(iii): Compound P can undergo bond fission when it is heated with a suitable oxidising agent to form two aldehydes S and T. H H H H [O] R C C R’ R R C R’ C + O O OH OH

  4. Q8(b)(ii)

    Summer 2024 · Unit 4

    2 marks4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2024 Unit 4, question 8(b)(ii): Describe a chemical test, giving reagent(s) and observations, to show that O pinacolone contains a C group. [2] CH3

  5. Q10(c)(i)

    Summer 2024 · Unit 4

    1 mark4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2024 Unit 4, question 10(c)(i): State what is seen when lactose reacts with the dark blue solution of Fehling’s reagent. [1]

  6. Q10(c)(ii)

    Summer 2024 · Unit 4

    1 mark4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2024 Unit 4, question 10(c)(ii): State which functional group must be present in a molecule of lactose for this result with Fehling’s reagent. [1]

  7. Q2

    Summer 2023 · Unit 4

    2 marks4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2023 Unit 4, question 2: State a group that will give a positive triiodomethane (iodoform) test and give the observation for a positive result. [2]

  8. Q12(b)(i)

    Summer 2023 · Unit 4

    1 mark4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2023 Unit 4, question 12(b)(i): Stage 1 is a nucleophilic addition reaction. Give the formula of the nucleophile taking part in this stage. [1]

  9. Q12(b)(ii)

    Summer 2023 · Unit 4

    1 mark4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2023 Unit 4, question 12(b)(ii): State why Stage 1 is described as an addition reaction. [1]

  10. Q12(b)(iii)

    Summer 2023 · Unit 4

    1 mark4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2023 Unit 4, question 12(b)(iii): State a reagent used for hydrolysis in Stage 2 [1]

  11. Q6(a)

    Summer 2022 · Unit 4

    1 mark4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2022 Unit 4, question 6(a): State the type of mechanism occurring during this reaction. [1]

  12. Q6

    Summer 2019 · Unit 4

    2 marks4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2019 Unit 4, question 6: Describe a simple chemical test that will distinguish between pentan-2-one and 1-phenylbutanone. [2] CH3 C CH2 CH2 CH3 C CH2 CH2 CH3 O O pentan-2-one 1-phenylbu

  13. Q9(a)(ii)

    Summer 2019 · Unit 4

    1 mark4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2019 Unit 4, question 9(a)(ii): Carbonyl compound U reacted with 2,4-dinitrophenylhydrazine to produce a solid derivative. State the colour of this solid derivative. [1]

  14. Q9(a)(iii)

    Summer 2019 · Unit 4

    4 marks4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2019 Unit 4, question 9(a)(iii): I. 9.8 δ. State what can be deduced from this statement. [1] II. The melting temperatures of the 2,4-dinitrophenylhydrazine derivatives can be used to identify

  15. Q9(a)(iv)

    Summer 2019 · Unit 4

    2 marks2.5 Hydrocarbons4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2019 Unit 4, question 9(a)(iv): Use your answer to part (iii) and other relevant information given in the question to give the structure of alkene T. Name alkene T. [2] Name

  16. Q9(b)(iv)

    Summer 2019 · Unit 4

    2 marks4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2019 Unit 4, question 9(b)(iv): Propenal reacts with hydrogen cyanide by a nucleophilic addition reaction. Complete the mechanism for this reaction using curly arrows and partial/complete char

  17. Q1(a)

    Summer 2018 · Unit 4

    1 mark4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2018 Unit 4, question 1(a): Complete the equation below, which shows the reaction of benzaldehyde with hydrogen cyanide. [1] H + HCN C O

  18. Q1(b)

    Summer 2018 · Unit 4

    1 mark4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2018 Unit 4, question 1(b): Give the formula of the nucleophile that takes part in the reaction shown in part (a). [1] (b)

  19. Q6(b)(i)

    Summer 2018 · Unit 4

    1 mark4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2018 Unit 4, question 6(b)(i): Give the formula of the yellow precipitate. [1]

  20. Q6(b)(ii)

    Summer 2018 · Unit 4

    2 marks4.4 Aldehydes and ketones
    The whole paper ↗
    Summer 2018 Unit 4, question 6(b)(ii): Suggest a structural formula for this isomer and identify the group that enables it to produce this yellow precipitate. [2] Structural formula Group
All 27 questions on Aldehydes and ketones, as a list
  1. Summer 2025, Unit 4, Q2(a) (1 mark): State what is seen, if anything, when propan-2-ol reacts with an alkaline solution of iodine. [1]
  2. Summer 2025, Unit 4, Q7(c) (3 marks): Each of the four compounds whose formulae are shown below are isomers. Compound Formula O R C OCH3 O H3C C S OH O CH3O C T H O HO C U CH3 Select the compound th
  3. Summer 2024, Unit 4, Q8(a)(iii) (4 marks): Compound P can undergo bond fission when it is heated with a suitable oxidising agent to form two aldehydes S and T. H H H H [O] R C C R’ R R C R’ C + O O OH OH
  4. Summer 2024, Unit 4, Q8(b)(ii) (2 marks): Describe a chemical test, giving reagent(s) and observations, to show that O pinacolone contains a C group. [2] CH3
  5. Summer 2024, Unit 4, Q10(c)(i) (1 mark): State what is seen when lactose reacts with the dark blue solution of Fehling’s reagent. [1]
  6. Summer 2024, Unit 4, Q10(c)(ii) (1 mark): State which functional group must be present in a molecule of lactose for this result with Fehling’s reagent. [1]
  7. Summer 2023, Unit 4, Q2 (2 marks): State a group that will give a positive triiodomethane (iodoform) test and give the observation for a positive result. [2]
  8. Summer 2023, Unit 4, Q12(b)(i) (1 mark): Stage 1 is a nucleophilic addition reaction. Give the formula of the nucleophile taking part in this stage. [1]
  9. Summer 2023, Unit 4, Q12(b)(ii) (1 mark): State why Stage 1 is described as an addition reaction. [1]
  10. Summer 2023, Unit 4, Q12(b)(iii) (1 mark): State a reagent used for hydrolysis in Stage 2 [1]
  11. Summer 2022, Unit 4, Q6(a) (1 mark): State the type of mechanism occurring during this reaction. [1]
  12. Summer 2019, Unit 4, Q6 (2 marks): Describe a simple chemical test that will distinguish between pentan-2-one and 1-phenylbutanone. [2] CH3 C CH2 CH2 CH3 C CH2 CH2 CH3 O O pentan-2-one 1-phenylbu
  13. Summer 2019, Unit 4, Q9(a)(ii) (1 mark): Carbonyl compound U reacted with 2,4-dinitrophenylhydrazine to produce a solid derivative. State the colour of this solid derivative. [1]
  14. Summer 2019, Unit 4, Q9(a)(iii) (4 marks): I. 9.8 δ. State what can be deduced from this statement. [1] II. The melting temperatures of the 2,4-dinitrophenylhydrazine derivatives can be used to identify
  15. Summer 2019, Unit 4, Q9(a)(iv) (2 marks): Use your answer to part (iii) and other relevant information given in the question to give the structure of alkene T. Name alkene T. [2] Name
  16. Summer 2019, Unit 4, Q9(b)(iv) (2 marks): Propenal reacts with hydrogen cyanide by a nucleophilic addition reaction. Complete the mechanism for this reaction using curly arrows and partial/complete char
  17. Summer 2018, Unit 4, Q1(a) (1 mark): Complete the equation below, which shows the reaction of benzaldehyde with hydrogen cyanide. [1] H + HCN C O
  18. Summer 2018, Unit 4, Q1(b) (1 mark): Give the formula of the nucleophile that takes part in the reaction shown in part (a). [1] (b)
  19. Summer 2018, Unit 4, Q6(b)(i) (1 mark): Give the formula of the yellow precipitate. [1]
  20. Summer 2018, Unit 4, Q6(b)(ii) (2 marks): Suggest a structural formula for this isomer and identify the group that enables it to produce this yellow precipitate. [2] Structural formula Group
  21. Summer 2018, Unit 4, Q6(c)(i) (1 mark): State a reagent that can be used to produce octane-2,3-diol from octane-2,3-dione. [1]
  22. Summer 2018, Unit 4, Q6(c)(ii) (1 mark): Suggest how the rate of the reaction in part (i) could be studied. [1]
  23. Summer 2018, Unit 4, Q7(c)(i) (1 mark): State what is seen when 2,4-DNPH is used to identify an aldehyde or a ketone. [1]
  24. Summer 2018, Unit 4, Q7(c)(ii) (1 mark): Explain why 2,4-DNPH is an appropriate reagent to use in their identification. [1]
  25. Summer 2017, Unit 4, Q4 (1 mark): State the reagent used to produce phenylmethanol from benzaldehyde. [1]
  26. Summer 2017, Unit 4, Q11(a)(i) (3 marks): Draw the mechanism for this reaction. Name the type of reaction mechanism occurring. [3] Mechanism type
  27. Summer 2017, Unit 4, Q12(a) (6 marks): Queen bees secrete a pheromone, compound W, which is used for a number of purposes, both inside and outside the hive. Compound W • is a straight chain aliphatic

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