Question

9. Give a reason why
• a] Heating a platinum wire is a reversible change but, heating a magnesium wire is an
irreversible change.
b] Addition of zinc nitrate to water is a physical change but, addition of zinc to dilute nitric
acid is a chemical change.
c) Rusting of iron is a chemical change but, magnetization of iron is a physical change.
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Answer 1

Explanation:

1 because it can be reversed but heating a magnesium wire is an irreversible change because it cannot be reversed

2 3Zn (NO3)2 +NO +4H2O