Sodium chloride solution contains hydrogen ions and hydroxide ions. Where do these two ions come from?
From the dissolved salt splitting up into its ions in the water
From a small number of water molecules breaking down in the solution
From the inert electrodes reacting with the solution as it is used
From the gases produced dissolving back into the solution again
40 exam-style questions on AQA GCSE Chemistry 4.3 Electrolysis, covering 4.3.1a The process of electrolysis, 4.3.1b Half equations in electrolysis, 4.3.2 Electrolysis of molten ionic compounds, 4.3.3 Using electrolysis to extract metals, 4.3.4 Electrolysis of aqueous solutions, and 4.3.5 Representation of reactions at electrodes as half equations. Each one has a worked solution and a mark scheme showing where the marks go.