Magnesium metal is made in industry by electrolysing molten magnesium chloride, MgCl2\text{MgCl}_2MgCl2, using inert electrodes. An engineer suggests electrolysing magnesium chloride solution instead, to save the energy needed to melt the compound.
Write the half equation for the formation of magnesium at the negative electrode.
Explain why the engineer's suggestion would not produce magnesium. Include a half equation in 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.