Which of the following is an example of a chemical change in matter?

• A. Melting of ice
• B. Dissolving sugar in water
• C. Boiling of water
• D. Rusting of iron

Answer: (D)

Verified step by step guidance

1. Understand the difference between physical and chemical changes: A physical change affects the form of a substance but not its chemical composition, while a chemical change results in the formation of one or more new substances with different properties.
2. Analyze each option to determine if it involves a change in chemical composition:
3. Melting of ice is a physical change because it changes water from solid to liquid without altering its chemical structure (H\_2O remains H\_2O).
4. Dissolving sugar in water is a physical change because sugar molecules disperse in water but do not chemically react or change their structure.
5. Boiling of water is a physical change because it changes water from liquid to gas without changing its chemical identity.
6. Rusting of iron is a chemical change because iron reacts with oxygen and moisture in the air to form a new substance, iron oxide, which has different properties from elemental iron.