Nigel Baldwin | Electrolysis of magnesium sulfate solution Part 1 DSCN0200 @nigelbaldwin3184 | Uploaded April 2018 | Updated October 2024, 5 hours ago.
High School Chemistry

The electrolysis of magnesium sulfate solution on a small scale using carbon fibre electrodes.

Requirements:
0.1M solution of magnesium sulfate
carbon fibre electrodes
small glass sample tubes, approx. 20ml capacity, (alternatively small test-tubes could be used)
small crystallising basin
wooden splints
12v d.c. power pack
crocodile clips
electrical leads

The electrolysis of dilute magnesium solution yields colourless gases at both electrodes.

The gases can be collected.

The gas collected above the cathode burnt with a small explosive 'pop' when tested with a lit splint confirming it was hydrogen.

Not enough gas was collected above the anode for testing (although oxygen was predicted to have been produced).

Some degradation of the anode occurred during the electrolysis, as can be seen by the brown - yellow coloration of the electrolyte in the second movie clip Electrolysis of magnesium sulfate solution Part 2.

Other dilute solutions may be electrolysed using this simple set-up, but gloves will need to be worn and caution exercised depending on the nature of the electrolysis products.