Molten magnesium chloride, MgCl2\text{MgCl}_2MgCl2, is electrolysed.
Which row of the table shows the correct half-equations for the reactions occurring at each electrode?
| Cathode | Anode | |
|---|---|---|
| A | Mg2+→Mg+2e−\text{Mg}^{2+} \rightarrow \text{Mg} + 2\text{e}^-Mg2+→Mg+2e− | 2Cl−+2e−→Cl22\text{Cl}^- + 2\text{e}^- \rightarrow \text{Cl}_22Cl−+2e−→Cl2 |
| B | Mg2++2e−→Mg\text{Mg}^{2+} + 2\text{e}^- \rightarrow \text{Mg}Mg2++2e−→Mg | 2Cl−→Cl2+2e−2\text{Cl}^- \rightarrow \text{Cl}_2 + 2\text{e}^-2Cl−→Cl2+2e− |
| C | Mg2++2e−→Mg\text{Mg}^{2+} + 2\text{e}^- \rightarrow \text{Mg}Mg2++2e−→Mg | Cl−→Cl2+e−\text{Cl}^- \rightarrow \text{Cl}_2 + \text{e}^-Cl−→Cl2+e− |
| D | Mg2+→Mg+2e−\text{Mg}^{2+} \rightarrow \text{Mg} + 2\text{e}^-Mg2+→Mg+2e− | Cl−+e−→Cl2\text{Cl}^- + \text{e}^- \rightarrow \text{Cl}_2Cl−+e−→Cl2 |
A
B
C
D
34 exam-style questions on OCR GCSE Chemistry Electrolysis. Each one has a worked solution and a mark scheme showing where the marks go.