A student electrolyses three solutions, J, K and L, using graphite electrodes.
The table shows the solutions and the student's observations.
| Solution | Compound dissolved | At the cathode | At the anode |
|---|---|---|---|
| J | copper chloride | pink-brown solid | bubbles of gas |
| K | sodium chloride | bubbles of gas | bubbles of gas |
| L | sodium sulfate | bubbles of gas | bubbles of gas |
Name the pink-brown solid formed at the cathode in solution J.
Explain why hydrogen, and not sodium, forms at the cathode in solution K.
Name the gas formed at the anode in solution K. Describe a test for this gas.
Name the gas formed at the anode in solution L. Explain why this gas forms.
Predict the product at each electrode when potassium bromide solution is electrolysed.
52 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.