A student electrolyses a solution of one of these compounds using inert electrodes: copper(II) sulfate, sodium chloride or potassium nitrate.
The gas collected at the negative electrode gives a squeaky pop with a lit splint. The gas collected at the positive electrode relights a glowing splint.
Which compound was in the solution? Explain your answer.
76 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.