Table shows the positions of four metals relative to carbon in the reactivity series.
Table: The position of four metals relative to carbon in the reactivity series
| Metal | Position relative to carbon |
|---|---|
| Potassium | above carbon |
| Magnesium | above carbon |
| Zinc | below carbon |
| Copper | below carbon |
Use Table to give the two metals that must be extracted from their compounds by electrolysis.
Explain why these two metals cannot be extracted by heating their oxides with carbon.
Suggest two reasons why extracting a metal by electrolysis costs more than extracting it by heating its oxide with carbon.
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.