Which factor is listed as a way to increase the rate of a reaction?

• A. Surface area
• B. Temperature
• C. Mass of solvent
• D. Color of solution

Answer: (A)

Mixing the main idea: how fast a reaction happens boils down to how often reacting particles collide and have enough energy to react. Increasing the exposed surface area of a solid reactant means more particles are at the interface where the reaction can occur, so collisions with the other reactant happen more often. That rise in collision frequency speeds up the reaction rate. Temperature can also boost rate by giving particles more energy, but the change in surface area directly increases the number of productive collisions, which is why this factor is listed as a way to increase the rate. The mass of the solvent or the color of the solution doesn’t directly affect how often those collisions occur in the same fundamental way.