Why does zinc coating protect an iron nail from rusting even when the coating is scratched?
Answer and explanation
Correct answer: C. Zinc is more reactive and corrodes in preference to the iron
- Step 1: Zinc is above iron in the reactivity series.
- Step 2: It loses electrons first, so it is sacrificed while the iron is protected.
Answer
Zinc is more reactive and corrodes in preference to the iron.
Why not the others: Zinc is less reactive and forms a barrier: barrier protection is lost once scratched. Zinc reacts with water to make iron: zinc cannot form iron. Zinc stops oxygen reaching the nail: this would not work when scratched.
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