Which of the following is an example of a reversible physical change?

• A. Rusting of iron
• B. Melting ice to form liquid water
• C. Burning wood to produce ash
• D. Baking a cake

Answer: (B)

Verified step by step guidance

1. Understand the difference between physical and chemical changes: Physical changes affect the form of a substance but not its chemical composition, while chemical changes result in the formation of new substances.
2. Identify reversible changes: A reversible change is one where the original substance can be recovered by reversing the process, typically involving physical changes like changes in state.
3. Analyze each option: Rusting of iron, burning wood, and baking a cake all involve chemical changes because new substances are formed and these changes are generally irreversible.
4. Consider melting ice to liquid water: This is a physical change because it involves a change of state from solid to liquid without altering the chemical identity of water (H2O).
5. Conclude that melting ice is a reversible physical change because water can be refrozen back to ice, restoring the original state without any chemical transformation.