Is a change in color always indicative of a chemical reaction? Why or why not?

• A. No, because color change only occurs during phase changes, not chemical reactions.
• B. Yes, because color change is a unique property of chemical reactions.
• C. Yes, any color change always means a chemical reaction has occurred.
• D. No, because color change can also result from physical changes such as dissolving or mixing substances without altering their chemical composition.

Answer: (D)

Verified step by step guidance

1. Understand that a color change can occur due to both physical and chemical changes. It is important to distinguish between these two types of changes.
2. Recall that a chemical reaction involves the making or breaking of chemical bonds, resulting in new substances with different properties.
3. Recognize that physical changes, such as dissolving a substance in a solvent or mixing two substances, can also cause a change in color without altering the chemical identity of the substances involved.
4. Therefore, a color change alone is not definitive evidence of a chemical reaction; additional evidence such as gas formation, temperature change, or precipitate formation is often needed to confirm a chemical reaction.
5. Conclude that the correct understanding is: No, because color change can also result from physical changes such as dissolving or mixing substances without altering their chemical composition.