When concentrated sodium chloride solution (brine) is electrolysed using inert electrodes, hydrogen gas is formed at the cathode.
Write the half-equation for the formation of hydrogen gas, H2\text{H}_2H2, from hydrogen ions, H+\text{H}^+H+.
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.