Which of the following factors does NOT affect the rate of a chemical reaction?

The rate of a chemical reaction can be influenced by several factors, including temperature, concentration of reactants, and surface area. Each of these factors plays a significant role in how quickly reactants can convert into products.

Temperature affects reaction rates because increasing the temperature typically provides reactant molecules with more kinetic energy, leading to more frequent and effective collisions. Similarly, the concentration of reactants impacts how often molecules encounter each other; a higher concentration generally increases the number of collisions per unit time, thereby enhancing reaction rates.

Surface area plays a crucial role as well, especially for solid reactants. Breaking down a solid into smaller pieces increases its surface area, allowing more particles to be available for reaction at any given time, which enhances the overall rate.

On the other hand, the color of the reactants does not affect the rate of a reaction. Color is a physical property and does not influence the frequency or energy of collisions between molecules. Therefore, it has no bearing on how quickly or slowly a reaction occurs. This is why it is recognized as the factor that does not impact the rate of a chemical reaction.