Which of the following is a clue of a chemical change?

• A. Dissolving
• B. Color change
• C. Freezing
• D. Change of state

Answer: (B)

Color change is a clue of a chemical change because when substances react, they form new compounds with different colors, reflecting a change in chemical composition and how the material interacts with light. The others are typically physical changes: dissolving just mixes substances without changing their identity, freezing is a change from liquid to solid, and a change of state refers to those phase transitions. So, a color change signals that a chemical transformation has occurred.