Preventing rusting by galvanising
1 mark · EasyState what forms on iron when it rusts.
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Hydrated iron(III) oxide or rust
Also accept: hydrated iron(III) oxide; Fe2O3.xH2O; rust
Common mistakes: iron(II) oxide; iron oxide
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Marking points
B1 · 1 mark · States 'hydrated iron(III) oxide', 'Fe2O3.xH2O' or 'rust'.
Worked solution
Rust that forms on iron is hydrated iron(III) oxide, which can be written as Fe2O3·xH2O (where x is a variable number). It is commonly called 'rust'.