Which of the following is a chemical change?
Which of the following is a chemical change?
Solution
Option 1 -> Dissolving salt in water is a physical change; salt can be recovered by evaporation, no new substance forms.
Option 2 -> Rusting of iron is a chemical change; iron reacts with oxygen and moisture to form iron oxide (rust), a new substance.
Option 3 -> Boiling water is a physical change; water changes state from liquid to gas but remains H₂O.
Option 4 -> Melting ice is a physical change; ice changes state from solid to liquid but remains H₂O.
Hence, Option 2: Rusting of iron -> In a chemical change, new substances with different properties are formed and the change is usually irreversible. Rusting involves a chemical reaction where iron combines with oxygen to form iron oxide, making it the only chemical change among the given options. -> correct
Related questions:
2026: 14 May Shift 2
2025: 14 May Shift 1