Aluminium is manufactured by the electrolysis of aluminium oxide, Al2O3\mathrm{Al_{2}O_{3}}Al2O3, dissolved in molten cryolite. The electrolyte contains Al3+\mathrm{Al^{3+}}Al3+ ions and O2−\mathrm{O^{2-}}O2− ions. Oxygen is produced at the anode.
Write the half equation for the reaction at the cathode.
Write the half equation for the reaction at the anode.
Explain, in terms of electrons, why the reaction at the cathode is a reduction.
State the electrode at which oxidation takes place.
Copper chloride solution is electrolysed. Complete the half equation for the formation of copper: Cu2++____→Cu\mathrm{Cu^{2+}} + \_\_\_\_ \rightarrow \mathrm{Cu}Cu2++____→Cu Give the missing term.
Acidified water is electrolysed. Write the half equation for the formation of hydrogen at the cathode.
52 exam-style questions on Edexcel GCSE Chemistry 4.2 Electrolytic processes, covering 4.2.1 Electrolytes and the process of electrolysis, 4.2.2 Products of electrolysis using inert electrodes, 4.2.3 Half equations, oxidation and reduction in electrolysis, and 4.2.4 Electrolysis of copper sulfate and purifying copper. Each one has a worked solution and a mark scheme showing where the marks go.