Which of the following is NOT a potential sign of a chemical change?

• A. Change in state from solid to liquid
• B. Formation of a precipitate
• C. Change in color
• D. Production of a gas

Answer: (A)

Verified step by step guidance

1. Understand that a chemical change involves the formation of new substances with different chemical properties, while a physical change affects only the state or appearance without altering the chemical identity.
2. Identify the options given: change in state from solid to liquid, formation of a precipitate, change in color, and production of a gas.
3. Recognize that a change in state from solid to liquid (melting) is a physical change because the substance's chemical composition remains the same.
4. Note that formation of a precipitate, change in color, and production of a gas are all indicators of chemical changes because they involve the creation of new substances or chemical reactions.
5. Conclude that the option 'change in state from solid to liquid' is NOT a sign of a chemical change, but rather a physical change.