Which half equation represents the reaction at the positive electrode in the electrolysis of molten lead bromide?
Br−+e−→Br\text{Br}^- + \text{e}^- \rightarrow \text{Br}Br−+e−→Br
Br2+2e−→2Br−\text{Br}_2 + 2\text{e}^- \rightarrow 2\text{Br}^-Br2+2e−→2Br−
2Br−→Br2+2e−2\text{Br}^- \rightarrow \text{Br}_2 + 2\text{e}^-2Br−→Br2+2e−
2Br−+2e−→Br22\text{Br}^- + 2\text{e}^- \rightarrow \text{Br}_22Br−+2e−→Br2
40 exam-style questions on AQA GCSE Chemistry 4.3 Electrolysis, covering 4.3.1a The process of electrolysis, 4.3.1b Half equations in electrolysis, 4.3.2 Electrolysis of molten ionic compounds, 4.3.3 Using electrolysis to extract metals, 4.3.4 Electrolysis of aqueous solutions, and 4.3.5 Representation of reactions at electrodes as half equations. Each one has a worked solution and a mark scheme showing where the marks go.