Electrolysis — Paper 2 · IGCSE Sciences - Co-ordinated (Double) 0654

16 Aqueous copper(II) sulfate is electrolysed using carbon electrodes. What is produced at each electrode? anode cathode A copper oxygen B hydrogen copper C oxygen copper D oxygen hydrogen

1 marks

Answer: C

This question in 0654/21 May/June 2017

17 Molten zinc bromide and aqueous zinc bromide are electrolysed using inert electrodes. In which rows do the electrode products match the electrolyte? electrolyte cathode product anode product 1 aqueous zinc bromide hydrogen bromine 2 aqueous zinc bromide zinc bromine 3 molten zinc bromide hydrogen bromine 4 molten zinc bromide zinc bromine A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

1 marks

Answer: B

This question in 0654/22 May/June 2017

16 The electrolysis of concentrated aqueous sodium chloride is an important industrial process. During this process ««1«« is produced at the cathode and ««2«« is produced at the anode. The solution formed turns litmus ««3«« . Which words complete gaps 1, 2 and 3? 1 2 3 A hydrogen chlorine blue B hydrogen oxygen blue C sodium chlorine red D sodium oxygen red

1 marks

Answer: A

This question in 0654/23 May/June 2017

18 Which changes take place at the electrodes during electrolysis? anode cathode A negatively charged ions positively charged ions gain electrons lose electrons B negatively charged ions positively charged ions lose electrons gain electrons C positively charged ions negatively charged ions gain electrons lose electrons D positively charged ions negatively charged ions lose electrons gain electrons

1 marks

Answer: B

This question in 0654/21 Oct/Nov 2017

18 Which statement describes what happens during electrolysis? A Covalent compounds produce more complex substances. B Covalent compounds produce simpler substances. C Ionic compounds produce more complex substances. D Ionic compounds produce simpler substances.

1 marks

Answer: D

This question in 0654/21 Oct/Nov 2018

19 Which diagram shows equipment used to electroplate nickel with copper? A B power supply power supply + – + – nickel copper nickel copper molten aqueous copper chloride copper chloride C D power supply power supply + – + – copper nickel copper nickel molten aqueous copper chloride copper chloride

1 marks

Answer: D

This question in 0654/22 Oct/Nov 2018

18 Which substance does not undergo electrolysis? A aqueous copper chloride B copper wire C dilute sulfuric acid D molten lead(II) bromide

1 marks

Answer: B

This question in 0654/23 Oct/Nov 2018

17 What is the electrolyte that is used when a nickel spoon is electroplated with copper? A copper B copper sulfate solution C nickel sulfate solution D nickel

1 marks

Answer: B

This question in 0654/21 May/June 2019

18 Which row identifies the products of the electrolysis of the named electrolyte using carbon electrodes? product at product at electrolyte anode cathode A aqueous copper(II) sulfate oxygen copper B concentrated aqueous sodium chloride chlorine sodium C dilute sulfuric acid hydrogen oxygen D molten potassium bromide potassium bromine

1 marks

Answer: A

This question in 0654/22 May/June 2019

18 When concentrated aqueous sodium chloride is electrolysed, the remaining solution turns red litmus paper to blue. Which substance causes this colour change? A chlorine B hydrogen C hydrochloric acid D sodium hydroxide

1 marks

Answer: D

This question in 0654/23 May/June 2019

18 During the electrolysis of aluminium oxide, which ions are reduced and at which electrode does this reduction occur? A aluminium ions at the anode B aluminium ions at the cathode C oxide ions at the anode D oxide ions at the cathode

1 marks

Answer: B

This question in 0654/21 Oct/Nov 2019

18 Which particle is oxidised at the anode during the electrolysis of aqueous copper(II) sulfate using inert electrodes? A Cu2+ B H+ C OH– D SO4 2–

1 marks

Answer: C

This question in 0654/22 Oct/Nov 2019

18 Concentrated aqueous sodium chloride is electrolysed using inert electrodes. Which row describes how the number of sodium ions and of chloride ions changes during the electrolysis? number of number of sodium ions chloride ions A decreases decreases B decreases no change C no change decreases D no change no change

1 marks

Answer: C

This question in 0654/23 Oct/Nov 2019

17 The diagram shows the electrolysis of lead(II) bromide using inert electrodes. coloured fumes electrode X electrode Y grey solid electrolyte Which statement about this experiment is correct? A Electrode X is positively charged. B The coloured fumes are produced at the negative electrode. C The electrolyte is lead(II) bromide. D The grey solid is lead(II) bromide.

1 marks

Answer: C

This question in 0654/21 May/June 2020

17 The diagram shows the electrolysis of lead(II) bromide using inert electrodes. coloured fumes electrode X electrode Y grey solid electrolyte Which statement about this experiment is correct? A Electrode X is positively charged. B The coloured fumes are produced at the negative electrode. C The electrolyte is lead(II) bromide. D The grey solid is lead(II) bromide.

1 marks

Answer: C

This question in 0654/22 May/June 2020

17 The diagram shows the electrolysis of lead(II) bromide using inert electrodes. coloured fumes electrode X electrode Y grey solid electrolyte Which statement about this experiment is correct? A Electrode X is positively charged. B The coloured fumes are produced at the negative electrode. C The electrolyte is lead(II) bromide. D The grey solid is lead(II) bromide.

1 marks

Answer: C

This question in 0654/23 May/June 2020

16 Which row describes what happens at the electrodes during electrolysis? at the anode at the cathode A negative ions gain electrons positive ions lose electrons B negative ions lose electrons positive ions gain electrons C positive ions gain electrons negative ions lose electrons D positive ions lose electrons negative ions gain electrons

1 marks

Answer: B

This question in 0654/23 Oct/Nov 2020

17 Molten lead(II) bromide is electrolysed. Which equation represents the reaction at the cathode? A 2Br –  Br2 + 2e– B Br2 + 2e–  2Br – C Pb2+  Pb + 2e– D Pb2+ + 2e–  Pb

1 marks

Answer: D

This question in 0654/22 Feb/March 2021

16 Aqueous copper(II) sulfate is electrolysed using copper electrodes. What is the half-equation for the reaction at the cathode? A Cu + 2e–  Cu2+ B Cu  Cu2+ + 2e– C Cu2+ + 2e–  Cu D Cu2+  Cu + 2e–

1 marks

Answer: C

This question in 0654/22 May/June 2021

18 What are the electrode products when aqueous copper(II) sulfate is electrolysed using inert electrodes? anode cathode A copper hydrogen B copper oxygen C oxygen copper D oxygen hydrogen

1 marks

Answer: C

This question in 0654/23 May/June 2021

16 The diagram shows the electrolysis of a compound. switch + – P Q electrolyte When the switch is closed, the solution around electrode P turns orange because a halogen is formed. The positive electrode P is called the ……1……, and the halogen is ……2…… . Which words complete gaps 1 and 2? 1 2 A anode bromine B anode chlorine C cathode bromine D cathode chlorine

1 marks

Answer: A

This question in 0654/21 Oct/Nov 2021

17 The diagram shows the electrolysis of a compound. switch + – P Q electrolyte When the switch is closed, the solution around electrode P turns orange because a halogen is formed. The positive electrode P is called the ……1……, and the halogen is ……2…… . Which words complete gaps 1 and 2? 1 2 A anode bromine B anode chlorine C cathode bromine D cathode chlorine

1 marks

Answer: A

This question in 0654/22 Oct/Nov 2021

17 The diagram shows the electrolysis of a compound. switch + – P Q electrolyte When the switch is closed, the solution around electrode P turns orange because a halogen is formed. The positive electrode P is called the ……1……, and the halogen is ……2…… . Which words complete gaps 1 and 2? 1 2 A anode bromine B anode chlorine C cathode bromine D cathode chlorine

1 marks

Answer: A

This question in 0654/23 Oct/Nov 2021

16 Aluminium is extracted from aluminium oxide by electrolysis. What is added to aluminium oxide in this process? A concentrated aqueous sodium chloride B cryolite C dilute sulfuric acid D water

1 marks

Answer: B

This question in 0654/22 Feb/March 2022

17 Aqueous copper(II) sulfate is electrolysed using inert electrodes. Which statement about this electrolysis is correct? A Copper ions are attracted to the cathode. B Electrons move from the cathode to the anode. C Electrolyte ions are oxidised at the cathode. D Sulfate ions are reduced to sulfur dioxide.

1 marks

Answer: A

This question in 0654/21 May/June 2022

17 Which statement about electrolysis is correct? A At the anode, anions are oxidised by gaining electrons. B At the anode, cations are reduced by gaining electrons. C At the cathode, anions are oxidised by gaining electrons. D At the cathode, cations are reduced by gaining electrons.

1 marks

Answer: D

This question in 0654/22 May/June 2022

17 Aqueous copper(II) sulfate is electrolysed using carbon electrodes. Which row describes the observations and products at each electrode during this process? cathode observation cathode product anode observation anode product A bubbles hydrogen anode decreases in size copper(II) ions B bubbles hydrogen bubbles oxygen C orange-brown solid copper bubbles oxygen D orange-brown solid copper anode decreases in size copper(II) ions

1 marks

Answer: C

This question in 0654/23 May/June 2022

18 Copper(II) sulfate can be electrolysed using either carbon electrodes or copper electrodes. What happens to the concentration of copper(II) ions in the electrolyte during electrolysis using these electrodes? using carbon using copper electrodes electrodes A decreases decreases B decreases no change C no change decreases D no change increases

1 marks

Answer: B

This question in 0654/21 Oct/Nov 2022

18 Which ions gain and lose electrons during the electrolysis of concentrated aqueous sodium chloride? ions gaining ions losing electrons electrons A H+ Cl – B H+ OH– C Na+ Cl – D Na+ OH–

1 marks

Answer: A

This question in 0654/22 Oct/Nov 2022

18 Molten calcium bromide is electrolysed using inert electrodes. What is the ionic half-equation at the cathode? A Ca+ → Ca + e– B Ca+ + e– → Ca C Ca2+ → Ca + 2e– D Ca2+ + 2e– → Ca

1 marks

Answer: D

This question in 0654/23 Oct/Nov 2022

17 Dilute aqueous potassium chloride is electrolysed using inert electrodes. Which substance is produced at the cathode? A chlorine B hydrogen C oxygen D potassium

1 marks

Answer: B

This question in 0654/22 Feb/March 2023

18 Sodium hydroxide is manufactured by the electrolysis of concentrated aqueous sodium chloride. During the process, a gas is given off at each electrode and the aqueous sodium hydroxide collects around one of the electrodes. Which row identifies the gas at each electrode and the electrode around which the aqueous sodium hydroxide collects? electrode at which at the anode at the cathode sodium hydroxide collects A chlorine hydrogen cathode B chlorine hydrogen anode C oxygen chlorine cathode D oxygen chlorine anode

1 marks

Answer: A

This question in 0654/21 May/June 2023

18 Which statement about the extraction of aluminium from its ore by electrolysis is correct? A Aluminium gains electrons from the anode. B Aluminium ions are oxidised at the cathode. C Aluminium ore is called cryolite. D Aluminium oxide is in the electrolyte.

1 marks

Answer: D

This question in 0654/22 May/June 2023

17 Copper is refined by electrolysis. Which statements about this process are correct? 1 Aqueous copper(II) sulfate is the electrolyte. 2 Inert anodes are used. 3 Cu2+ ions are reduced at the cathode. 4 Pure copper is deposited at the anode. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

1 marks

Answer: B

This question in 0654/23 May/June 2023

17 Concentrated aqueous sodium chloride is electrolysed using inert electrodes. Which row describes how the number of sodium ions and the number of chloride ions changes during the electrolysis? number of number of sodium ions chloride ions A decreases decreases B decreases no change C no change decreases D no change no change

1 marks

Answer: C

This question in 0654/22 Oct/Nov 2023

18 Which statement correctly describes how aluminium is changed during the electrolysis of aluminium oxide? A At the anode, aluminium ions gain electrons and so are oxidised. B At the anode, aluminium ions lose electrons and so are oxidised. C At the cathode, aluminium ions gain electrons and so are reduced. D At the cathode, aluminium ions lose electrons and so are reduced.

1 marks

Answer: C

This question in 0654/23 Oct/Nov 2023

17 Aqueous copper(II) sulfate is electrolysed using carbon electrodes. Which row describes this electrolysis? oxygen is gas bubbles are copper ions are produced at the seen at the anode reduced negative electrode A no no no B yes yes yes C yes no yes D no yes no

1 marks

Answer: C

This question in 0654/22 Feb/March 2024

19 Two electrolysis experiments are done using inert electrodes. Experiment 1 is the electrolysis of aqueous copper(II) sulfate. Experiment 2 is the electrolysis of molten lithium bromide. Which row describes the products at each electrode in these experiments? experiment 1 experiment 2 cathode anode cathode anode A copper oxygen bromine lithium B oxygen copper lithium bromine C copper oxygen lithium bromine D oxygen copper bromine lithium

1 marks

Answer: C

This question in 0654/21 May/June 2024

17 Aqueous copper(II) sulfate is electrolysed using carbon electrodes. What is the ionic half-equation for the reaction at the cathode? A Cu2+ + 2e–  Cu B 2H+ + 2e–  H2 C Cu  Cu2+ + 2e– D 4OH–  O2 + 2H2O + 4e–

1 marks

Answer: A

This question in 0654/22 May/June 2024

16 Which row shows the ionic half-equation for the reaction at the cathode during the electrolysis of the named electrolyte? electrolyte equation A molten aluminium oxide Al 3+ + 3e–  Al B molten aluminium oxide 2O2–  O2 + 4e– C concentrated aqueous sodium chloride H2  2H+ + 2e– D concentrated aqueous sodium chloride Na+ + e–  Na

1 marks

Answer: A

This question in 0654/23 May/June 2024

18 Which statement describes what happens during electrolysis? A Covalent compounds produce more complex substances. B Covalent compounds produce simpler substances. C Ionic compounds produce more complex substances. D Ionic compounds produce simpler substances.

1 marks

Answer: D

This question in 0654/21 Oct/Nov 2024

16 Which statements about the electrolysis of aqueous copper(II) sulfate are correct? 1 Oxygen is produced at the anode when carbon electrodes are used. 2 Copper is produced at the cathode when copper electrodes are used. 3 Hydrogen is produced at the cathode when carbon electrodes are used. 4 Electrolysis does not occur when inert electrodes are used. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

1 marks

Answer: A

This question in 0654/22 Oct/Nov 2024

16 The diagram shows the electrolysis of molten lead(II) bromide using inert electrodes. coloured fumes electrode X electrode Y grey solid electrolyte Which statement about this experiment is correct? A Electrode X is positively charged. B The coloured fumes are produced at the negative electrode. C The electrolyte is lead(II) bromide. D The grey solid is lead(II) bromide.

1 marks

Answer: C

This question in 0654/23 Oct/Nov 2024

21 Which gas is formed at the cathode during electrolysis? A carbon dioxide B chlorine C hydrogen D oxygen

1 marks

Answer: C

This question in 0654/21 May/June 2025

16 During electrolysis, reactions occur at the cathode and anode. Which statements about the electrode reactions are correct? 1 At the anode, anions gain electrons and are reduced. 2 At the anode, anions lose electrons and are oxidised. 3 At the cathode, cations gain electrons and are reduced. 4 At the cathode, cations lose electrons and are oxidised. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

1 marks

Answer: C

This question in 0654/21 Oct/Nov 2025

16 Which changes take place at the electrodes during electrolysis? anode cathode A negatively charged ions positively charged ions gain electrons lose electrons B negatively charged ions positively charged ions lose electrons gain electrons C positively charged ions negatively charged ions gain electrons lose electrons D positively charged ions negatively charged ions lose electrons gain electrons

1 marks

Answer: B

This question in 0654/22 Oct/Nov 2025

14 Concentrated aqueous sodium chloride is electrolysed using inert electrodes. What is the ionic half-equation for the reaction at the cathode? A 2Cl –  Cl 2 + 2e– B 2H+ + 2e–  H2 C Na+ + e–  Na D NaCl  Na+ + Cl –

1 marks

Answer: B

This question in 0654/23 Oct/Nov 2025