During an investigation, a solution of sodium chloride was electrolysed.
A gas was produced at the positive electrode (anode).
The gas was tested with a piece of damp blue litmus paper.
The litmus paper turned red and was then bleached white.
Name the gas that was produced at the positive electrode.
83 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.