Exothermic waves have what effect on the solution during processing?

• A. Cool the solution
• B. Heat the solution
• C. Neutralize the solution
• D. Evaporate the solution

Answer: (B)

Exothermic means heat is released. During processing, the chemical reactions in the waving or neutralizing solutions release energy into the solution, warming it. That heat can speed up processing and change how the product interacts with the hair, so the solution gets hotter rather than cooler. Cooling would come from an endothermic process, neutralizing refers to changing pH at a different step, and evaporation would require the heat to drive liquid into vapor—neither is the primary effect of the exothermic reaction described.