A student is going to electrolyse five different solutions using inert electrodes.
Here is part of the reactivity series, with the most reactive first:
potassium, sodium, magnesium, zinc, (hydrogen), copper, silver
The student predicts the products at each electroden and the table shows the student's predictions.
| Solution | Predicted product at cathode (−) | Predicted product at anode (+) |
|---|---|---|
| potassium chloride | potassium | chlorine |
| copper sulfate | copper | sulfur |
| silver nitrate | silver | oxygen |
| sodium sulfate | sodium | oxygen |
| magnesium bromide | hydrogen | bromine |
Name a substance that can be used to make inert electrodes.
Evaluate the student's predictions.
Explain which predictions are correct and which are wrong, and give the correct products for any wrong predictions.
Use ideas about the ions present in each solution.
52 exam-style questions on OCR GCSE Chemistry 3.4 Electrolysis, covering 3.4.1 Products formed at the electrodes in electrolysis and 3.4.2 The technique of electrolysis. Each one has a worked solution and a mark scheme showing where the marks go.