Which of the following is NOT a physical change?

• A. Burning of magnesium ribbon
• B. Melting of ice
• C. Dissolving sugar in water
• D. Evaporation of alcohol

Answer: (A)

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 or just a change in physical state or appearance.
3. Melting of ice is a physical change because it involves changing 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 molecular structure.
5. Burning of magnesium ribbon is a chemical change because magnesium reacts with oxygen in the air to form magnesium oxide, a new substance with different chemical properties.