Which of the following is NOT a common factor affecting the rate of a chemical reaction?

• A. Color
• B. Temperature
• C. Concentration
• D. Catalysts

Answer: (A)

The rate of a chemical reaction depends on how often particles collide and have enough energy to react. Temperature increases kinetic energy and speeds up collisions, raising the rate. Higher concentration means more particles in the same space, leading to more frequent collisions and a faster rate. Catalysts provide an alternate pathway that requires less energy, so more collisions are effective and the rate increases.

Color, on the other hand, is just a property we observe about a substance. It doesn’t change how often particles collide, how much energy they have, or the energy barrier they must overcome. So it does not typically affect the rate of a reaction.