An electroplating experiment was conducted to refine copper using a pure copper cathode and an impure copper anode immersed in a copper(II) sulfate electrolyte.
The results of the experiment are shown below:
| Mass of cathode (g) | Appearance of electrolyte | |
|---|---|---|
| Before electrolysis | 2.34 | Blue solution |
| After electrolysis | 3.12 | Blue solution |
Explain why the intensity of the blue colour of the copper(II) sulfate solution did not change during the electrolysis.
83 exam-style questions on Edexcel GCSE Chemistry 4.2 Electrolytic processes, covering 4.2.1 Electrolytes and the process of electrolysis, 4.2.2 Products of electrolysis using inert electrodes, 4.2.3 Half equations, oxidation and reduction in electrolysis, and 4.2.4 Electrolysis of copper sulfate and purifying copper. Each one has a worked solution and a mark scheme showing where the marks go.