Magnesium is extracted by the electrolysis of molten magnesium chloride, MgCl2\text{MgCl}_2MgCl2.
Which equation shows the reaction at the anode in this electrolysis?
Mg2++2e−→Mg\text{Mg}^{2+} + 2\text{e}^- \rightarrow \text{Mg}Mg2++2e−→Mg
2Cl−−2e−→Cl22\text{Cl}^- - 2\text{e}^- \rightarrow \text{Cl}_22Cl−−2e−→Cl2
2H++2e−→H22\text{H}^+ + 2\text{e}^- \rightarrow \text{H}_22H++2e−→H2
4OH−−4e−→O2+2H2O4\text{OH}^- - 4\text{e}^- \rightarrow \text{O}_2 + 2\text{H}_2\text{O}4OH−−4e−→O2+2H2O
Practise OCR GCSE Chemistry Electrolysis with exam-style questions for Foundation and Higher tier. 45 questions, matched to the OCR GCSE Chemistry (J248) specification and written in Paper 1 and Paper 2 (Foundation Tier) or Paper 3 and Paper 4 (Higher Tier) style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.