Magnesium is extracted by the electrolysis of molten magnesium chloride, MgCl2\mathrm{MgCl_{2}}MgCl2. Chlorine gas is also produced.
Write half equations for the reactions at the cathode and at the anode.
Explain, in terms of electrons, which ions are oxidised and which ions are reduced.
Calculate the maximum mass of magnesium, in tonnes, that can be produced from 1.90 tonnes of magnesium chloride. Relative atomic mass: Mg = 24. Relative formula mass: MgCl2=95.1\mathrm{MgCl_{2}} = 95. 1MgCl2=95.1 tonne = 1.00 × 106 g
Calculate the volume of chlorine gas, in dm3\mathrm{dm^{3}}dm3, produced from 1.90 tonnes of magnesium chloride. One mole of any gas occupies 24 dm3\mathrm{dm^{3}}dm3 at room temperature and pressure.
Explain why magnesium cannot be produced by electrolysing magnesium chloride solution.
52 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.