O-LevelChemistryElectrolysis5070/12 · Oct/Nov 2017 · Q161 Mark

Magnesium can be produced by electrolysis of molten magnesium chloride, MgCl2. What are the equations for the reactions that occur at the positive electrode and at the negative electrode?

A2Cl- → Cl2 + 2e- (positive electrode); 2H+ + 2e- → H2 (negative electrode)

BCl2 + 2e- → 2Cl- (positive electrode); Mg2+ + 2e- → Mg (negative electrode)

C2Cl- → Cl2 + 2e- (positive electrode); Mg2+ + 2e- → Mg (negative electrode)

D2Cl- → Cl2 + 2e- (positive electrode); Mg2+ + 2e- → 2Mg (negative electrode)

✓ Correct answer

C: 2Cl- → Cl2 + 2e- (positive electrode); Mg2+ + 2e- → Mg (negative electrode)

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Topic: Electrolysis, O-Level Chemistry (syllabus 5070). Multiple choice, 1 mark.
Source: O-Level Chemistry, Oct/Nov 2017 Paper 1 Variant 2, question 16.

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