What happens to the weight of iron, when it rusts?
- ADecreases then increases
- BIncreases then decreases
- CRemains same
- DIt increases for a long time
- ENone of the above/More than one of the above
Show answer and explanation
Correct answer: (d) It increases for a long time
Explanation
Rusting is the corrosion of iron in presence of oxygen and moisture, forming hydrated iron oxide (Fe2O3·xH2O).
Oxygen and water join the metal, so the weight of the rusting iron increases, and it goes on increasing as long as the iron rusts.
Flaky rust can later fall off and leave a lighter piece, but the Commission’s final key takes the weight as increasing: option (d).