What this practice covers
These questions are drawn from past CIE 0620 Chemistry papers and filtered to corrosion of metals. 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 corrosion of metals, taken from our own topic notes. Read them before you practise and you will recognise the traps in the questions.
- Saying rusting needs only air, or only water.
- Naming rust as iron(II) oxide, or as iron oxide with no mention of water.
- Saying rust protects the iron underneath, which is what aluminium oxide does and rust does not.
- Using the word rusting for copper or aluminium.
- Saying galvanising works only as a barrier, missing the sacrificial half.
- Choosing a metal below iron for sacrificial protection.
- Forgetting to boil the water in test tube 2, so the experiment does not exclude oxygen.
- Saying salt causes rusting, when it accelerates a process that needs oxygen and water anyway.
Revise it first
If any of the above is unfamiliar, work through the notes before practising: Corrosion of metals revision notes.