Chemistry 0620 · IGCSE · Electrolysis

Electrolysis — practice question

In the electrolysis of dilute sulfuric acid with inert electrodes, what are the ionic half-equations for the processes occurring at each electrode?

  • Apositive: $2\text{H}^+ + 2e^- \rightarrow \text{H}_2$ ; negative: $4\text{OH}^- \rightarrow 2\text{H}_2\text{O} + \text{O}_2 + 4e^-$
  • Bpositive: $2\text{H}^+ + 2e^- \rightarrow \text{H}_2$ ; negative: $4\text{OH}^- + 4\text{H}^+ \rightarrow 4\text{H}_2\text{O}$
  • Cpositive: $4\text{OH}^- \rightarrow 2\text{H}_2\text{O} + \text{O}_2 + 4e^-$ ; negative: $2\text{H}^+ + 2e^- \rightarrow \text{H}_2$
  • Dpositive: $4\text{OH}^- + 4\text{H}^+ \rightarrow 4\text{H}_2\text{O}$ ; negative: $2\text{H}^+ + 2e^- \rightarrow \text{H}_2$

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