What this practice covers
These questions are drawn from past CIE 0620 Chemistry papers and filtered to electrolysis. You answer, you find out immediately whether you were right, and you get the reasoning for the correct option and for each distractor. Wrong answers go to a mistakes locker so you can come back to exactly those.
Practice is free. You need an account only so your progress and your mistakes are still there next time.
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What examiners see students get wrong here
These are the errors that cost marks on electrolysis, taken from our own topic notes. Read them before you practise and you will recognise the traps in the questions.
- Saying the anode is negative. The anode is positive, and anions go to it.
- Trying to electrolyse a solid ionic compound. It must be molten or aqueous.
- Predicting sodium at the cathode from aqueous sodium chloride.
- Saying electrons move through the electrolyte.
- Writing a half-equation with the electrons on the wrong side. Cathode reactions take electrons in, anode reactions give them out.
- Confusing the two gas tests: hydrogen pops with a lighted splint and oxygen relights a glowing splint.
- Saying the blue colour fades when copper electrodes are used. It fades only with inert electrodes.
Revise it first
If any of the above is unfamiliar, work through the notes before practising: Electrolysis revision notes.