Electrochemistry — IGCSE Chemistry (0620) questions by topic
Describing the electrolysis apparatus used to extract aluminium, working out oxidation numbers in the aluminium and copper(II) oxide reaction, identifying which particles carry charge through the external circuit, and predicting the products at each electrode when molten zinc oxide is electrolysed are the recurring demands in this topic, worth 1 to 16 marks across 47 real questions from 2023 to 2025 papers.
Identify, state, name, write and explain lead the command words, and write here means the correct half-equation or product name for a specific electrode, not a general description of electrolysis. Because anode and cathode products are easy to swap under pressure, working through several electrolysis scenarios and checking each prediction against instant marking is a reliable way to confirm the correct electrode has been matched to the correct product every time.
May–June 2025, Paper 11
Concentrated aqueous sodium chloride is electrolysed using inert electrodes. What is the main product formed at the positive electrode (anode)? A chlorine B hydrogen C oxygen D…
Answer this question and get it marked →May–June 2025, Paper 12
The diagram shows a simple electrolytic cell for an electrolysis experiment. A battery is connected to two electrodes dipping into a liquid in a beaker. The electrode connected to…
Answer this question and get it marked →May–June 2025, Paper 13
Which row describes the electrolysis of molten potassium bromide? product at anode product at cathode --- --- --- A bromine hydrogen B bromine potassium C hydrogen bromine D…
Answer this question and get it marked →May–June 2025, Paper 21
The diagram shows the electroplating of a steel object. A power supply has its positive (+) terminal connected to a copper electrode and its negative (−) terminal connected to the…
Answer this question and get it marked →Concentrated aqueous sodium chloride is electrolysed using inert electrodes. Which equation shows the correct ionic half-equation for the reaction at the anode? A. Cl⁻ + e⁻ → Cl…
Answer this question and get it marked →May–June 2025, Paper 22
Molten zinc oxide is electrolysed using inert electrodes. Which row identifies the product at each electrode? anode cathode --- --- --- A zinc oxygen B hydrogen oxygen C oxygen…
Answer this question and get it marked →Dilute aqueous sodium chloride is electrolysed using platinum electrodes. What is the half-equation for the reaction at the cathode? A 2H^+ + 2e^- - H2 B Na^+ + e^- - Na C 2Cl^- -…
Answer this question and get it marked →Hydrogen-oxygen fuel cells can be used to power vehicles. Which statement about hydrogen-oxygen fuel cells is correct? A The equation for the overall reaction is H2 + O2 - H2O2. B…
Answer this question and get it marked →May–June 2025, Paper 23
Which particles are responsible for the transfer of charge in the external circuit during the electrolysis of molten lead(II) bromide? A anions B atoms C cations D electrons
Answer this question and get it marked →Concentrated aqueous copper(II) chloride is electrolysed using carbon electrodes. What is formed at each electrode? negative electrode positive electrode --- --- --- A chlorine…
Answer this question and get it marked →May–June 2025, Paper 42
This question is about electrolysis. Complete the definition of electrolysis by filling in the missing words. "The decomposition of ........................................…
Answer this question and get it marked →May–June 2024, Paper 11
Dilute sulfuric acid and lead(II) bromide are electrolysed separately. Which statements are correct? 1 Colourless gases are produced when dilute sulfuric acid is electrolysed. 2…
Answer this question and get it marked →Which equation represents an oxidation reaction? A CaCO3 → CaO + CO2 B 4FeO + O2 → 2Fe2O3 C 2NO2 → N2O4 D 2P2O5 → P4O10
Answer this question and get it marked →May–June 2024, Paper 12
In an experiment, a molten compound is broken down using electricity. Which row identifies the negative electrode and the general name for the molten compound being broken down?…
Answer this question and get it marked →Which of the reactions show the underlined substance being reduced? 1 CuO + H2 → Cu + H2O (CuO underlined) 2 2Mg + O2 → 2MgO (Mg underlined) 3 MgO + 2HCl → MgCl2 + H2O (MgO…
Answer this question and get it marked →May–June 2024, Paper 13
Iron water taps are often electroplated with a layer of chromium. Which statements explain why iron water taps are electroplated? 1 It improves the appearance of the taps. 2 It…
Answer this question and get it marked →Molten caesium bromide is electrolysed using inert electrodes. Which row identifies the product at each electrode? (columns: anode; cathode) A bromine; caesium B caesium; bromine…
Answer this question and get it marked →In a blast furnace, iron is extracted when iron(III) oxide reacts with carbon monoxide: Fe2O3 + 3CO → 2Fe + 3CO2 Which substance is oxidised and which is reduced in this reaction?…
Answer this question and get it marked →May–June 2024, Paper 21
A metal object is electroplated with copper. One electrode is the metal object and the other electrode is copper. The electrolyte is aqueous copper(II) sulfate. Which row shows…
Answer this question and get it marked →Which statement about electrolysis is correct? A Chemical energy is converted to electrical energy. B Electrons flow through the electrolyte. C Ionic compounds are broken down. D…
Answer this question and get it marked →The equation for the reaction of magnesium with carbon dioxide is shown: 2Mg + CO2 → 2MgO + C Which statement about this reaction is correct? A Magnesium is oxidised and carbon…
Answer this question and get it marked →May–June 2024, Paper 22
Which statement about electrolysis is correct? A Electrons move through the electrolyte from the cathode to the anode. B Electrons move in the external circuit towards the…
Answer this question and get it marked →Aqueous copper(II) sulfate is electrolysed using copper electrodes. What is the half-equation for the reaction at the cathode? A 2H⁺ + 2e⁻ → H2 B 4OH⁻ → O2 + 2H2O + 4e⁻ C Cu →…
Answer this question and get it marked →Which equation represents a redox reaction? A AgNO3 + NaCl → AgCl + NaNO3 B PCl5 + 4H2O → H3PO4 + 5HCl C 3Fe + 4H2O → Fe3O4 + 4H2 D MgCO3 + 2HCl → MgCl2 + CO2 + H2O
Answer this question and get it marked →The equation for the reaction between aluminium and copper(II) oxide is shown: 2Al + 3CuO → Al2O3 + 3Cu Which statements about this equation are correct? 1 The oxidation number of…
Answer this question and get it marked →May–June 2024, Paper 23
Aqueous copper(II) sulfate is electrolysed using copper electrodes connected to a d.c. power supply. Which statement describes what happens during the electrolysis? A Copper atoms…
Answer this question and get it marked →Electrolysis is carried out on concentrated aqueous potassium bromide using inert electrodes. Which products are formed at the anode and the cathode? (columns: anode; cathode) A…
Answer this question and get it marked →The equation for a redox reaction is shown: H2O2 + 2KI + H2SO4 → I2 + K2SO4 + 2H2O "Potassium iodide is ...(1)... agent in this reaction because iodide ions ...(2)... electrons."…
Answer this question and get it marked →May–June 2024, Paper 32
Fig. 3.1 shows the apparatus used to electrolyse molten magnesium chloride, with a + / - power supply, electrodes dipping into the molten magnesium chloride, an unreactive gas…
Answer this question and get it marked →May–June 2024, Paper 33
Molten calcium bromide is electrolysed. Define the term electrolysis.
Answer this question and get it marked →October–November 2024, Paper 11
The diagram shows the apparatus used to electroplate a nickel shape with silver. A power supply is connected to a silver rod and a nickel shape, both dipping in an electrolyte.…
Answer this question and get it marked →Concentrated aqueous sodium chloride and dilute sulfuric acid are each electrolysed separately using inert electrodes. Three statements about the electrolysis of these…
Answer this question and get it marked →October–November 2024, Paper 12
Molten sodium sulfide, Na2S, is electrolysed using inert electrodes. Which row identifies the product at each electrode? cathode anode --- --- --- A sodium sulfur B sulfur sodium…
Answer this question and get it marked →October–November 2024, Paper 13
What is the definition of electrolysis? A the formation of a positive ion by the removal of electrons using an electric current B the decomposition of an ionic compound, when…
Answer this question and get it marked →Which statement about electroplating a copper spoon with silver is correct? A Both the anode and cathode are made of carbon. B The copper spoon is the anode. C Aqueous copper(II)…
Answer this question and get it marked →October–November 2024, Paper 21
The apparatus used for electrolysis is shown (a d.c. power supply connected via + and - to two electrodes dipping in an electrolyte). Which statement is correct? A Copper forms at…
Answer this question and get it marked →Which statement about the electrolysis of aqueous copper(II) sulfate is correct? A When copper electrodes are used, the solution turns from blue to colourless. B When graphite…
Answer this question and get it marked →The apparatus used for the extraction of aluminium by electrolysis is shown: a carbon anode (positive) dips into a solution of aluminium oxide in molten cryolite held in a cell…
Answer this question and get it marked →October–November 2024, Paper 22
Aqueous copper(II) sulfate is electrolysed using graphite electrodes. Which row identifies the product and observations at each electrode during the electrolysis? anode product…
Answer this question and get it marked →Molten sodium chloride is electrolysed using inert electrodes. Which row shows the products formed at the cathode and anode? cathode anode --- --- --- A chlorine hydrogen B…
Answer this question and get it marked →October–November 2024, Paper 23
Two different substances are electrolysed using inert electrodes in two separate experiments. Hydrogen is produced in both experiments. Which row identifies the two substances and…
Answer this question and get it marked →Aqueous copper(II) sulfate can be electrolysed using either carbon electrodes or copper electrodes. Which statement describes what happens at the positive electrode? A Copper is…
Answer this question and get it marked →Aluminium is extracted from aluminium oxide by electrolysis. The ionic half-equation for the reaction at one of the electrodes is shown. Al3+ + 3e- - Al Which row describes the…
Answer this question and get it marked →October–November 2024, Paper 43
This question is about electrolysis. State the meaning of the term electrolysis.
Answer this question and get it marked →October–November 2024, Paper 62
A teacher uses the apparatus shown in Fig. 1.1 to pass an electric current through molten mercury(II) bromide at a temperature of 300 °C. Fig. 1.1 shows a power supply connected…
Answer this question and get it marked →May–June 2023, Paper 41
This question is about electricity and chemical reactions. The electrolysis of concentrated aqueous potassium bromide using graphite electrodes forms hydrogen at the cathode and…
Answer this question and get it marked →May–June 2023, Paper 43
This question is about electricity and chemical reactions. Aqueous copper(II) sulfate is an electrolyte. The electrolysis of aqueous copper(II) sulfate using inert electrodes…
Answer this question and get it marked →Other IGCSE Chemistry topics
- Organic chemistry (155)
- The Periodic Table (102)
- Metals (96)
- Acids, bases and salts (84)
- Experimental techniques and chemical analysis (84)
- Chemical reactions (80)
- Stoichiometry (62)
- Chemical bonding (58)
- Chemistry of the environment (55)
- Atoms, elements and compounds (51)
- Practical skills (43)
- States of matter (42)