Which of the following processes does not involve a change in chemical properties?

• A. Digestion of food
• B. Rusting of iron
• C. Burning of wood
• D. Melting of ice

Answer: (D)

Verified step by step guidance

1. Understand that a change in chemical properties involves a chemical reaction where the substance's chemical identity changes, forming new substances.
2. Analyze each process: Digestion of food involves breaking down complex molecules into simpler ones through chemical reactions, so it changes chemical properties.
3. Rusting of iron is a chemical reaction between iron and oxygen forming iron oxide, which is a new substance, so it changes chemical properties.
4. Burning of wood is combustion, a chemical reaction producing new substances like carbon dioxide and ash, so it changes chemical properties.
5. Melting of ice is a physical change where solid water turns into liquid water without altering the chemical composition (H₂O remains H₂O), so it does not involve a change in chemical properties.