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Electrolysis: OCR GCSE Combined Science A questions

Every OCR GCSE Combined Science A exam question on C3.4 Electrolysis, 2018–2025, with its mark scheme and examiner’s report.

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3,411 questions

  1. Q13(b)

    June 2025 · Chemistry Paper 3 Foundation

    1 markC3.4 Electrolysis
    The whole paper ↗

  2. Q13(c)(i)

    June 2025 · Chemistry Paper 3 Foundation

    1 markC3.4 Electrolysis
    The whole paper ↗

  3. Q13(c)(ii)

    June 2025 · Chemistry Paper 3 Foundation

    1 markC3.4 Electrolysis
    The whole paper ↗

  4. Q13(c)(iii)

    June 2025 · Chemistry Paper 3 Foundation

    1 markC3.4 Electrolysis
    The whole paper ↗

  5. Q15(c)

    June 2025 · Chemistry Paper 9 Higher

    3 marksC3.4 Electrolysis
    The whole paper ↗

  6. Q4

    June 2024 · Chemistry Paper 3 Foundation

    1 markC3.4 Electrolysis
    The whole paper ↗
    Your answer

  7. Q12(b)

    June 2024 · Chemistry Paper 9 Higher

    1 markC3.4 Electrolysis
    The whole paper ↗

  8. Q12(c)

    June 2024 · Chemistry Paper 9 Higher

    2 marksC3.4 Electrolysis
    The whole paper ↗

  9. Q12(d)

    June 2024 · Chemistry Paper 9 Higher

    2 marksC3.4 Electrolysis
    The whole paper ↗

  10. Q12(a)

    June 2023 · Chemistry Paper 3 Foundation

    1 markC3.4 Electrolysis
    The whole paper ↗

  11. Q12(b)

    June 2023 · Chemistry Paper 3 Foundation

    2 marksC3.4 Electrolysis
    The whole paper ↗

  12. Q12(c)

    June 2023 · Chemistry Paper 3 Foundation

    2 marksC3.4 Electrolysis
    The whole paper ↗

  13. Q12(d)(i)

    June 2023 · Chemistry Paper 3 Foundation

    2 marksC3.4 Electrolysis
    The whole paper ↗

  14. Q12(d)(ii)

    June 2023 · Chemistry Paper 3 Foundation

    1 markC3.4 Electrolysis
    The whole paper ↗

  15. Q12(d)(iii)

    June 2023 · Chemistry Paper 3 Foundation

    1 markC3.4 Electrolysis
    The whole paper ↗

  16. Q12(d)(iv)

    June 2023 · Chemistry Paper 3 Foundation

    1 markC3.4 Electrolysis
    The whole paper ↗

  17. Q11(e)

    June 2023 · Chemistry Paper 4 Foundation

    1 markC3.4 Electrolysis
    The whole paper ↗

  18. Q14

    June 2023 · Chemistry Paper 9 Higher

    6 marksC3.4 Electrolysis
    The whole paper ↗

  19. Q6

    June 2022 · Chemistry Paper 3 Foundation

    1 markC3.4 Electrolysis
    The whole paper ↗
    Your answer

  20. Q12(c)

    June 2022 · Chemistry Paper 9 Higher

    4 marksC3.4 Electrolysis
    The whole paper ↗
All 52 questions on Electrolysis, as a list
  1. June 2025, Chemistry Paper 3 Foundation, Q13(b) (1 mark): Sodium chloride can be split up into its elements using electrolysis. During electrolysis, sodium chloride must be heated until it is a liquid. The table shows
  2. June 2025, Chemistry Paper 3 Foundation, Q13(c)(i) (1 mark): What is the name of the piece of equipment, X? [1]
  3. June 2025, Chemistry Paper 3 Foundation, Q13(c)(ii) (1 mark): Name the gas produced at the anode. [1]
  4. June 2025, Chemistry Paper 3 Foundation, Q13(c)(iii) (1 mark): A student thinks that the electrodes (anode and cathode) should be inert and made from graphite. Complete the sentences to explain why the student is correct. P
  5. June 2025, Chemistry Paper 9 Higher, Q15(c) (3 marks): The electrolysis of a sodium hydroxide solution produces hydrogen at the cathode rather than sodium. Explain why. [3]
  6. June 2024, Chemistry Paper 3 Foundation, Q4 (1 mark): Zinc chloride is an ionic compound made from Zn2+ and Cl – ions. 4 What is made at the negative electrode during the electrolysis of molten zinc chloride? A Chl
  7. June 2024, Chemistry Paper 9 Higher, Q12(b) (1 mark): Explain why potassium bromide must be molten for electrolysis to happen. [1]
  8. June 2024, Chemistry Paper 9 Higher, Q12(c) (2 marks): State the product made at the cathode and write the half equation for the reaction. Product Half equation [2]
  9. June 2024, Chemistry Paper 9 Higher, Q12(d) (2 marks): The electrolysis is repeated with a solution of potassium bromide. A student thinks that the same product will be formed at the cathode. Explain why the student
  10. June 2023, Chemistry Paper 3 Foundation, Q12(a) (1 mark): The equation for the reaction is CuCl 2( ) Cu(s) + Cl 2(g) Complete the balanced symbol equation for the reaction by writing in the missing state symbol for cop
  11. June 2023, Chemistry Paper 3 Foundation, Q12(b) (2 marks): The student thinks that the experiment shows that electrode X is the cathode. Explain why the student is correct. Use the diagram. [2]
  12. June 2023, Chemistry Paper 3 Foundation, Q12(c) (2 marks): Use the data in the table to show that the mass of copper produced doubles as the current doubles. [2]
  13. June 2023, Chemistry Paper 3 Foundation, Q12(d)(i) (2 marks): Plot a graph of the results on the grid. [2]
  14. June 2023, Chemistry Paper 3 Foundation, Q12(d)(ii) (1 mark): Draw a line of best fit. [1] 0.20 0.18 0.16 0.14 0.12 Mass of copper 0.10 (g) 0.08 0.06 0.04 0.02 0.00 0 1 2 3 4 5 6 Current (A)
  15. June 2023, Chemistry Paper 3 Foundation, Q12(d)(iii) (1 mark): The student thinks that the result for the mass of copper produced at 3 A is incorrect. Explain how the student knows this result is incorrect. [1]
  16. June 2023, Chemistry Paper 3 Foundation, Q12(d)(iv) (1 mark): Use your graph to predict the mass of copper that should have been produced at 3 A. Mass of copper produced = g [1]
  17. June 2023, Chemistry Paper 4 Foundation, Q11(e) (1 mark): The reaction where a metal is extracted using electrolysis. [1]
  18. June 2023, Chemistry Paper 9 Higher, Q14 (6 marks): 14* Copper sulfate solution, CuSO4, contains copper ions, Cu2+, and sulfate ions, SO4 2–. A student extracts copper from copper sulfate solution using electroly
  19. June 2022, Chemistry Paper 3 Foundation, Q6 (1 mark): The diagram shows the electrolysis of molten copper chloride, CuCl 2. Power supply X Y Molten copper chloride Chlorine is formed at electrode X and copper is fo
  20. June 2022, Chemistry Paper 9 Higher, Q12(c) (4 marks): A student electrolyses potassium chloride. The diagram shows the equipment they use. Wooden splints Battery Solid potassium chloride The student’s experiment do
  21. June 2022, Chemistry Paper 9 Higher, Q12(d) (3 marks): In the successful electrolysis of potassium chloride, potassium is made at the cathode. Explain how potassium atoms are made from potassium ions. [3]
  22. June 2022, Chemistry Paper 10 Higher, Q14 (6 marks): 14* Sodium is extracted from molten sodium chloride, NaCl, by electrolysis. Sodium produced by this process is expensive. Sodium chloride is an ionic compound.
  23. November 2021, Chemistry Paper 3 Foundation, Q6 (1 mark): The diagram shows the electrolysis of molten lead bromide. Anode Cathode Molten lead bromide Which row in the table shows the products formed at the anode and t
  24. November 2021, Chemistry Paper 4 Foundation, Q15(a) (2 marks): Look at the equation for the electrolysis of aluminium oxide. Al 2O3 Al + O2 Complete the balanced symbol equation for the reaction. [2]
  25. November 2021, Chemistry Paper 4 Foundation, Q15(b)(i) (2 marks): Explain why the aluminium oxide must be molten during electrolysis. [2]
  26. November 2021, Chemistry Paper 4 Foundation, Q15(b)(ii) (1 mark): Explain why aluminium is produced at the cathode. [1]
  27. November 2021, Chemistry Paper 10 Higher, Q3 (1 mark): An aqueous solution of sodium chloride, NaCl , is electrolysed using inert electrodes. Which product is formed at the cathode? A Chlorine B Hydrogen C Oxygen D
  28. November 2021, Chemistry Paper 10 Higher, Q10 (1 mark): Look at the equations. Na+ + e− Na 2Cl − Cl 2 + 2e− They show the two half equations that happen during the electrolysis of molten sodium chloride. What is the
  29. November 2021, Chemistry Paper 10 Higher, Q16(a) (2 marks): The copper(II) sulfate solution contains copper ions, Cu2+. Write the balanced half equation for the formation of copper at the cathode. Include state symbols i
  30. November 2021, Chemistry Paper 10 Higher, Q16(b)(i) (1 mark): The student decides that the result for the mass of copper formed at the cathode at 2 A is incorrect. Give a reason for this result. [1]
  31. November 2021, Chemistry Paper 10 Higher, Q16(b)(ii) (1 mark): Has the student drawn the correct line of best fit? Give a reason for your answer. [1]
  32. November 2021, Chemistry Paper 10 Higher, Q16(b)(iii) (2 marks): Explain how repeating the experiment could improve the accuracy of the results. [2]
  33. November 2021, Chemistry Paper 10 Higher, Q16(c) (3 marks): Use the graph to calculate the mass of copper produced by a current of 15 A. Give your answer to 1 significant figure. Mass of copper = g [3]
  34. November 2020, Chemistry Paper 3 Foundation, Q5 (1 mark): The electrolysis of aluminium oxide, Al,Oz, makes aluminium, Al, and oxygen, O2: 5 2ALO3 → 4A1+ 30½ Which statement about electrolysis is correct? A The masses
  35. November 2020, Chemistry Paper 9 Higher, Q17(a) (2 marks): Explain the term electrolysis. [2]
  36. November 2020, Chemistry Paper 9 Higher, Q17(b) (1 mark): Electrolysis involves the reactions of cations and anions. Describe the difference between cations and anions. [1]
  37. November 2020, Chemistry Paper 9 Higher, Q17(c)(i) (1 mark): Write the balanced half equation for the formation of potassium. [1]
  38. November 2020, Chemistry Paper 9 Higher, Q17(c)(ii) (2 marks): State and explain if this equation shows oxidation or reduction. [2]
  39. November 2020, Chemistry Paper 9 Higher, Q17(d) (2 marks): Name the product formed at the cathode when an aqueous solution of potassium chloride, KCl (aq), is electrolysed. Give a reason for your answer. [2]
  40. November 2020, Chemistry Paper 9 Higher, Q17(e) (2 marks): Name the product formed at the anode when an aqueous solution of potassium chloride, KCl (aq), is electrolysed. Give a reason for your answer. [2]
  41. June 2019, Chemistry Paper 3 Foundation, Q5 (1 mark): Na+ is a positively charged ion. 5 What is the name given to a positively charged ion? A Anion B Cathode C Cation D Electrolyte Your answer [1]
  42. June 2019, Chemistry Paper 9 Higher, Q14(a)(i) (2 marks): Identify the two ions attracted to the negative electrode (cathode). 1 2 [2]
  43. June 2019, Chemistry Paper 9 Higher, Q14(a)(ii) (2 marks): State and explain which product is formed at the negative electrode (cathode). [2]
  44. June 2019, Chemistry Paper 9 Higher, Q14(b) (2 marks): Electrolysis can also be carried out on molten ionic compounds such as magnesium oxide, MgO. During the electrolysis of molten magnesium oxide, magnesium ions,
  45. June 2018, Chemistry Paper 3 Foundation, Q13(a)(i) (2 marks): Complete the labels on the diagram. Power pack + – [2]
  46. June 2018, Chemistry Paper 3 Foundation, Q13(a)(ii) (2 marks): Sodium chloride is an ionic compound. Sodium chloride • Will not conduct electricity when it is solid • Will conduct electricity when it is dissolved in water.
  47. June 2018, Chemistry Paper 3 Foundation, Q13(b) (3 marks): A scientist electrolyses three different compounds. Complete the table below to show what products will be formed. Product formed at Product formed at Compound
  48. June 2018, Chemistry Paper 3 Foundation, Q13(c) (2 marks): Electrolysis can also be used to electroplate one metal onto another. Look at the diagram of this experiment. – + Silver Ring being plated Water The experiment
  49. June 2018, Chemistry Paper 9 Higher, Q8 (1 mark): Which of the following happens at a cathode? A Gain of electrons by anions B Gain of electrons by cations C Loss of electrons by anions D Loss of electrons by c
  50. June 2018, Chemistry Paper 10 Higher, Q17(c) (1 mark): Aluminium is made at the negative electrode (cathode) from aluminium ions, Al 3+. Write a half equation for this reaction. Use e− to represent an electron. [1]
  51. June 2018, Chemistry Paper 10 Higher, Q17(d) (2 marks): Oxygen, O2, is made at the positive electrode (anode). The anodes in the cell have to be replaced every few weeks. Suggest why. [2]
  52. June 2018, Chemistry Paper 10 Higher, Q17(e) (2 marks): Write the overall balanced symbol equation for the electrolytic breakdown of aluminium oxide, Al 2O3. [2]

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