plumiElectrolysis: OCR GCSE Chemistry A questions
Every OCR GCSE Chemistry A exam question on C3.4 Electrolysis, 2018–2025, with its mark scheme and examiner’s report.
Paper
All papers
Exam
All years
Calculations
- Your answer
- Your answer
Q23(c)
The whole paper ↗- Your answer
- Your answer
Q21(d)(i)
The whole paper ↗Q21(d)(ii)
The whole paper ↗- Your answer
- Your answer
- Your answer
Q20(a)
The whole paper ↗Q20(c)(i)
The whole paper ↗Q20(c)(ii)
The whole paper ↗Q20(d)
The whole paper ↗Q20(e)
The whole paper ↗Q19(a)
The whole paper ↗Q19(b)
The whole paper ↗Q19(c)
The whole paper ↗- Your answer
- Your answer
All 61 questions on Electrolysis, as a list
- June 2025, Paper 1 Foundation, Q11 (1 mark): Molten copper chloride is electrolysed. What is made at the positive electrode (anode)? A Chlorine B Copper C Hydrogen D Oxygen Your answer [1]
- June 2025, Paper 3 Higher, Q14 (1 mark): Copper chloride solution is electrolysed. What is the half equation for the reaction at the negative electrode (cathode)? 2Cl – Cl 2 + 2e– A Cu2+ + 2e– B Cu 2H+
- June 2025, Paper 3 Higher, Q23(c) (4 marks): Chromium is used for electroplating. Chromium atoms lose electrons at the anode. Chromium ions, Cr3+, gain electrons at the cathode. Write balanced half equatio
- June 2024, Paper 1 Foundation, Q14 (1 mark): The electrolysis of molten copper chloride makes copper metal and chlorine gas. Which row describes what happens to the inert electrodes during the electrolysis
- June 2024, Paper 1 Foundation, Q15 (1 mark): The diagram shows the electrolysis of molten sodium chloride. dc power supply – + Anode Cathode Molten sodium chloride Which products are made in the electrolys
- June 2024, Paper 1 Foundation, Q21(d)(i) (2 marks): Which form of carbon should you choose to use as an electrode in an electrolysis experiment with a molten electrolyte? Explain your answer. Form of carbon Reaso
- June 2024, Paper 1 Foundation, Q21(d)(ii) (1 mark): All of the melting points in the table are high. Why is it important that electrodes used in a molten electrolyte have a high melting point? Tick (3) one box. E
- June 2024, Paper 3 Higher, Q6 (1 mark): Which equipment is needed to set up an electrolysis experiment? A A battery, a beaker, a funnel and wires B A battery, a beaker, electrodes and wires C A batter
- June 2024, Paper 3 Higher, Q7 (1 mark): Which products are formed in the electrolysis of sodium chloride solution? Anode Cathode A chlorine hydrogen B chlorine sodium C oxygen hydrogen D oxygen sodium
- June 2024, Paper 3 Higher, Q11 (1 mark): Molten aluminium oxide, Al 2O3, is electrolysed. Which row of the table shows the reactions at the electrodes? Cathode Anode Al 3+ + 3e– O2– O2 + 2e– A Al Al 3+
- June 2023, Paper 1 Foundation, Q20(a) (3 marks): Some possible steps they can use in the electrolysis experiment are listed. 1. Put test tubes over the electrodes to collect gases. 2. Weigh each electrode. 3.
- June 2023, Paper 1 Foundation, Q20(c)(i) (1 mark): Estimate how much oxygen will be made in experiment 4. Volume of oxygen made = cm3 [1]
- June 2023, Paper 1 Foundation, Q20(c)(ii) (1 mark): Describe the relationship between the amount of copper made and the amount of oxygen made. [1]
- June 2023, Paper 1 Foundation, Q20(d) (1 mark): Copper sulfate solution is an electrolyte. What type of compound is an electrolyte? Tick (3) one box. Covalent Ionic Molecular [1]
- June 2023, Paper 1 Foundation, Q20(e) (2 marks): Another teacher repeats the electrolysis experiment. They record the mass of the electrode at the start of the experiment. At the end of the experiment, they re
- June 2023, Paper 3 Higher, Q19(a) (6 marks): A scientist wants to make copper using electrolysis. They consider two different electrolysis experiments using inert electrodes as shown in the table. Experime
- June 2023, Paper 3 Higher, Q19(b) (2 marks): Another scientist investigates the electrolysis of lead bromide. The diagram shows their experiment. + – Anode Cathode Solid lead bromide The experiment does no
- June 2023, Paper 3 Higher, Q19(c) (2 marks): Complete the balanced half equation for the production of bromine from bromide ions. 2Br – – [2]
- June 2022, Paper 1 Foundation, Q9 (1 mark): During the electrolysis of molten sodium chloride, sodium and chlorine are formed. What happens at the positive electrode (anode)? The chloride ion, Cl –, gains
- June 2022, Paper 1 Foundation, Q15 (1 mark): Which products are formed in the electrolysis of aqueous copper sulfate, CuSO4 using inert electrodes? A Copper and oxygen B Copper and sulfur dioxide C Hydroge
- June 2022, Paper 2 Foundation, Q23(c) (1 mark): Gas Z turns damp blue litmus paper white. State the name of gas Z. [1]
- June 2022, Paper 3 Higher, Q8 (1 mark): Molten sodium chloride can be electrolysed. What is the correct half equation for the reaction at the negative electrode (cathode)? 2Cl – – 2e– A Cl 2 2H+ + 2e–
- June 2022, Paper 3 Higher, Q19(a)(i) (1 mark): Draw a line of best fit on the graph. [1]
- June 2022, Paper 3 Higher, Q19(a)(ii) (1 mark): What is the volume of hydrogen gas given off after 23 minutes? Volume of hydrogen gas = cm3 [1]
- June 2022, Paper 3 Higher, Q19(a)(iii) (1 mark): Which electrode is hydrogen gas given off at? [1]
- June 2022, Paper 3 Higher, Q19(a)(iv) (1 mark): State the name of the product made at the other electrode. [1]
- June 2022, Paper 3 Higher, Q19(b) (3 marks): A student repeats the teacher’s experiment with aqueous copper sulfate, CuSO4. The student finds that no hydrogen gas is given off. Explain why hydrogen gas is
- June 2022, Paper 3 Higher, Q19(c) (3 marks): In the electrolysis of aqueous copper sulfate, copper is also made. The teacher sets up an experiment to measure the volume of oxygen gas made. Measuring cylind
- June 2022, Paper 4 Higher, Q17(c) (1 mark): Gas Z turns damp blue litmus paper white. State the name of gas Z. [1]
- November 2021, Paper 1 Foundation, Q12 (1 mark): Molten lead bromide, PbBr2, is electrolysed. Which substance is formed at the cathode? A Bromine B Hydrogen C Lead D Oxygen Your answer [1]
- November 2021, Paper 3 Higher, Q20(a) (1 mark): In both experiments, copper is deposited at the cathode. Describe a difference between the electrolysis of copper sulfate solution using inert graphite electrod
- November 2021, Paper 3 Higher, Q20(b)(i) (2 marks): Hydrogen gas, H2, is formed at the cathode. Write the balanced half equation for this reaction. Use e– to represent an electron. [2]
- November 2021, Paper 3 Higher, Q20(b)(ii) (1 mark): State the name of the substance made at the anode. [1]
- November 2021, Paper 3 Higher, Q20(b)(iii) (2 marks): Sodium chloride cannot conduct electricity when it is solid. Explain why sodium chloride can conduct electricity when it is dissolved in water but not when it i
- November 2021, Paper 3 Higher, Q20(c) (3 marks): The student investigates materials to use as inert electrodes in the electrolysis of aqueous sodium chloride. They compare four materials A, B, C, and D. Their
- November 2020, Paper 1 Foundation, Q11 (1 mark): An aqueous solution of concentrated sodium chloride is electrolysed. Bubbles are seen at the positive electrode. What is the name of the substance produced at t
- November 2020, Paper 1 Foundation, Q18(a)(i) (2 marks): Look at the diagram of an electrolysis experiment. Complete the diagram using the words in the list. You may use each word once, more than once or not at all. c
- November 2020, Paper 1 Foundation, Q18(a)(ii) (2 marks): A teacher demonstrates the electrolysis of molten lead bromide. Predict the products made at each electrode. Positive electrode Negative electrode [2]
- November 2020, Paper 1 Foundation, Q18(b)(i) (3 marks): Plot a graph of the student’s results and draw a line of best fit. 3.5 3.0 2.5 2.0 Mass of copper produced (g) 1.5 1.0 0.5 0 0 0.2 0.4 0.6 0.8 1.0 Current (A) [
- November 2020, Paper 1 Foundation, Q18(b)(ii) (1 mark): Use your graph to estimate the current needed to make 2.25 g of copper. Current = A [1]
- November 2020, Paper 1 Foundation, Q18(b)(iii) (2 marks): Use your graph, and a calculation, to find the mass of copper that would be produced using 15 A. Give your answer to 2 significant figures. Mass of copper produ
- November 2020, Paper 3 Higher, Q23(a) (2 marks): Write the formulae of the ions that are present in aqueous copper sulfate solution. [2]
- November 2020, Paper 3 Higher, Q23(b) (1 mark): Why is it important that the investigation is done with inert electrodes? [1]
- November 2020, Paper 3 Higher, Q23(c)(i) (1 mark): Which aqueous solution would you use to electroplate a metal spoon with copper using a safe method? Tick (3) one box. Copper sulfate Zinc bromide Copper chlorid
- November 2020, Paper 3 Higher, Q23(c)(ii) (2 marks): Give two reasons for your answer to (c)(i). 1 2 [2]
- November 2020, Paper 3 Higher, Q23(d)(i) (1 mark): Predict the product made at the anode when sodium sulfate solution is electrolysed. [1]
- November 2020, Paper 3 Higher, Q23(d)(ii) (1 mark): Hydrogen gas is made at the cathode instead of sodium metal. Explain why. [1]
- November 2020, Paper 3 Higher, Q23(d)(iii) (2 marks): Write the balanced half equation for the formation of hydrogen gas. Use e− to represent an electron. [2]
- November 2020, Paper 3 Higher, Q23(e) (1 mark): The electrolysis products of ionic compounds can be different in the molten or aqueous states. Suggest why. [1]
- June 2019, Paper 1 Foundation, Q14 (1 mark): During the electrolysis of molten copper chloride, what is made at the positive electrode (anode)? A Chloride B Chlorine C Copper D Hydrogen Your answer [1]
- June 2019, Paper 3 Higher, Q14 (1 mark): During the electrolysis of molten lead bromide, bromine is made at the anode. Which half equation shows that bromine is made at the anode? 2Br− Br2 + 2e− A Br−
- June 2019, Paper 3 Higher, Q21(b) (6 marks): Sodium chloride, NaCl, is an ionic compound. Sodium chloride forms a giant ionic lattice that can be represented using different models. Look at the diagrams. T
- June 2018, Paper 1 Foundation, Q20(a) (2 marks): Plot the results on the grid. The first 3 points have been done for you. Draw a line of best fit. [2] 20 18 16 14 12 Volume of hydrogen 10 (cm3) 8 6 4 2 0 0 2 4
- June 2018, Paper 1 Foundation, Q20(b) (1 mark): One of the results is anomalous. [1] Circle the anomalous result on the graph.
- June 2018, Paper 1 Foundation, Q20(c) (1 mark): Sulfuric acid contains these particles. H+ OH– H2O SO4 2– Which particles are attracted to the anode? [1]
- June 2018, Paper 1 Foundation, Q20(d) (2 marks): The student also investigates the electrolysis of some molten (liquid) salts. Complete the table. Molten salt Formula Product at cathode Product at anode Potass
- June 2018, Paper 3 Higher, Q24(a) (2 marks): Complete the table to show the products at each electrode. Experiment What happens at cathode (–) What happens at anode (+) 1 Oxygen made 2 Copper deposited [2]
- June 2018, Paper 3 Higher, Q24(b) (1 mark): Copper electrodes are non-inert electrodes. What is meant by non-inert electrodes? [1]
- June 2018, Paper 3 Higher, Q24(c) (2 marks): Look at the results for experiment 2 using copper electrodes. At the cathode copper ions, Cu2+ gain electrons to make copper atoms. Write the half equation for
- June 2018, Paper 3 Higher, Q24(d) (2 marks): The student also electrolyses sodium chloride solution using platinum (inert) electrodes. At the cathode, hydrogen gas is made rather than sodium metal. Explain
- June 2018, Paper 4 Higher, Q8 (1 mark): Aluminium is extracted by the electrolysis of molten aluminium oxide, Al 2O3. Which equation shows the reaction at the anode in this electrolysis? 4OH– – 4e– →
Questions, mark schemes and examiner’s reports are © OCR, from their published past papers. Plumi isn’t affiliated with any exam board. Want whole papers? Every OCR GCSE Chemistry A paper.
Rather write your answers by hand on iPad? Plumi marks them against the same mark schemes.