Preventing rusting by galvanising
2 marks · NormalState the two conditions necessary for the rusting of iron.
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Both oxygen and water must be present.
Also accept: air and moisture; oxygen and moisture
Common mistakes: Only oxygen; Only water; Only moisture
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Marking points
B1 · 1 mark · States water/moisture is needed for rusting.
B2 · 1 mark · States oxygen/air is needed for rusting.
Worked solution
The two conditions needed for rusting of iron are the presence of oxygen (from air) and water (moisture). Both must be present for rusting to occur.