The electrolysis of other molten substances
2 marks · NormalWrite the ionic half-equations for the electrolysis of molten magnesium chloride. Identify which half-equation is for the cathode and which is for the anode.
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Also accept: Mg^{2+} + 2e^- \to Mg; 2Cl^- \to Cl_2 + 2e^-; 2Cl^- \to Cl_2 + 2e^-; Mg^{2+} + 2e^- \to Mg
Common mistakes: Put electrons on the wrong side; Unbalanced with respect to charge or atoms
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Marking points
B1 · 1 mark · Correct half-equation for Mg2+ at the cathode (Mg^{2+} + 2e^- \to Mg)
B2 · 1 mark · Correct half-equation for Cl- at the anode (2Cl^- \to Cl_2 + 2e^-)
Worked solution
At the cathode: reduction occurs.
At the anode: oxidation occurs.