Which two substances are needed for iron to rust?
Answer and explanation
Correct answer: A. Oxygen and water
- Step 1: Rusting is a slow oxidation of iron.
- Step 2: It needs both oxygen and water.
Answer
Oxygen and water.
Why not the others: Carbon dioxide and nitrogen: these are not required for rusting. Hydrogen and oxygen: hydrogen is not needed. Nitrogen and water: oxygen is needed.
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