Why can rusting begin when a painted iron surface is scratched?
Answer and explanation
Correct answer: The scratch exposes iron to oxygen in air and moisture.
A paint coating acts as a barrier between iron and the environment. At a scratch, iron becomes exposed to oxygen from air and moisture. In their presence, iron can undergo oxidation to form hydrated iron(III) oxide, or rust. Option B is incorrect because paint does not produce oxygen; the scratch merely removes the protective barrier.
Frequently asked questions
What is the correct answer to this question?
The scratch exposes iron to oxygen in air and moisture.
Why is this the correct answer?
A paint coating acts as a barrier between iron and the environment. At a scratch, iron becomes exposed to oxygen from air and moisture. In their presence, iron can undergo oxidation to form hydrated iron(III) oxide, or rust. Option B is incorrect because paint does not produce oxygen; the scratch merely removes the protective barrier.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
