A student is investigating the electrolysis of copper(II) sulfate solution.
He does two experiments.
Experiment 1 uses inert carbon (graphite) electrodes. Experiment 2 uses copper electrodes.
Complete the table to show the products or observations at each electrode.
| Experiment | What happens at cathode (−-−) | What happens at anode (+++) |
|---|---|---|
| 1 | ............................................................ | Oxygen gas is produced |
| 2 | Copper is deposited | ............................................................ |
Copper electrodes are non-inert electrodes in this setup. What is meant by non-inert electrodes?
Look at the results for experiment 2 using copper electrodes. At the cathode, copper(II) ions, Cu2+\text{Cu}^{2+}Cu2+, gain electrons to make copper atoms. Write the half equation for this reaction. Use e−\text{e}^-e−\ to represent an electron.
The student also electrolyses sodium chloride solution using carbon (inert) electrodes. At the cathode, hydrogen gas is made rather than sodium metal. Explain why.