Which statement is a common misconception about chemical reactions?

• A. Dissolving always means a reaction has occurred.
• B. Reactions always require heat.
• C. Bubbles always indicate boiling.
• D. All chemical reactions produce color changes.

Answer: (A)

Dissolving is usually a physical process, not a chemical change. When a substance dissolves, its particles are dispersed in the solvent, but you don’t necessarily form new substances. The chemical identity of the solute remains the same (you can often recover the original solid by evaporating the solvent, showing there was no new compound created). For example, table salt or sugar dissolves in water without undergoing a chemical reaction.

A chemical reaction, by contrast, involves making new substances with different properties. You’d typically see signs like a new solid forming (precipitation), gas bubbles that aren’t simply from boiling, or a noticeable energy change beyond what happens during dissolution. Color changes can happen, but aren’t required for a reaction to have occurred.

So the statement that dissolving always means a reaction has occurred is a common misconception because dissolving usually reflects a physical change, not the formation of new substances. The other ideas—heat being required for all reactions, bubbles equaling boiling, and all reactions changing color—are not universally true.