Chemistry 5070 · O Level · Electrolysis

Electrolysis — practice question

Magnesium may be obtained by electrolysing molten magnesium chloride, $\text{MgCl}_2$. What are the equations for the reactions taking place at the positive electrode and at the negative electrode?

  • APositive: $2\text{Cl}^- \rightarrow \text{Cl}_2 + 2e^-$; Negative: $2\text{H}^+ + 2e^- \rightarrow \text{H}_2$
  • BPositive: $\text{Cl}_2 + 2e^- \rightarrow 2\text{Cl}^-$; Negative: $\text{Mg}^{2+} + 2e^- \rightarrow \text{Mg}$
  • CPositive: $2\text{Cl}^- \rightarrow \text{Cl}_2 + 2e^-$; Negative: $\text{Mg}^{2+} + 2e^- \rightarrow \text{Mg}$
  • DPositive: $2\text{Cl}^- \rightarrow \text{Cl}_2 + 2e^-$; Negative: $\text{Mg}^{2+} + 2e^- \rightarrow 2\text{Mg}$

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