What substance is used to speed up a chemical reaction in hair coloring?

The substance used to speed up a chemical reaction in hair coloring is a catalyst. In the context of hair coloring, a catalyst facilitates the oxidation process that occurs when hair color is applied. This process is crucial because it allows the color molecules to penetrate the hair shaft more effectively and results in a more vibrant and long-lasting color. Catalysts do not alter the final outcome of the reaction; instead, they enhance the rate at which the reaction occurs without being consumed in the process.

While options such as a buffer zone and bumping the base pertain to hair coloring techniques, they do not specifically refer to substances that increase reaction rates. Breakage refers to damage that can occur to hair, which is not a factor in accelerating chemical reactions. Consequently, the use of a catalyst is essential for achieving optimal results in hair coloring by ensuring that the chemical reactions happen more efficiently.