A student electrolyses aqueous sodium bromide using inert electrodes and measures the pH of the solution before and after the electrolysis.
Which statement about the pH of the solution is correct?
It becomes acidic, because hydroxide ions are discharged in place of bromide ions.
It becomes acidic, because sodium ions are discharged in place of hydrogen ions.
It becomes alkaline, because hydroxide ions build up in the solution.
It stays neutral, because hydrogen and bromine are both removed from it.
98 exam-style questions on OCR GCSE Chemistry 3.4 Electrolysis, covering 3.4.1 Products formed at the electrodes in electrolysis and 3.4.2 The technique of electrolysis. Each one has a worked solution and a mark scheme showing where the marks go.