Which statement about processing temperature is true?

• A. Lower temperature speeds up the reaction
• B. Temperature has no effect on processing
• C. Higher temperature slows down the reaction
• D. Higher temperature speeds up the reaction

Answer: (D)

Temperature affects how fast chemical reactions happen. When it’s warmer, molecules move faster, collide more often, and with more energy. If those collisions exceed the activation energy needed for the reaction, bonds break and reform more quickly, so the processing reaction proceeds faster. In hair processing, applying warmth speeds up the chemical changes in the processing solution, which is why processing times can be reduced with heat. But too much heat can over-process or damage hair, so it must be used within the recommended range. So the true statement is that higher temperature speeds up the reaction.