How does increasing the concentration of reactants affect the rate of reaction?

Increasing the concentration of reactants enhances the rate of reaction primarily due to the increased likelihood of collisions between reactant particles. When the concentration is higher, there are more particles of the reactants present in a given volume. This increase in particle number leads to a higher frequency of effective collisions, which are necessary for a reaction to occur.

In a chemical reaction, particles must collide with sufficient energy and proper orientation to break existing bonds and form new ones. With a greater concentration, the chance of these effective collisions occurring rises, consequently speeding up the overall reaction rate. This relationship is a fundamental concept in reaction kinetics, illustrating how concentration directly influences the frequency of reactant interactions.

Therefore, as the concentration of reactants increases, the rate at which the reaction progresses also increases, confirming that the correct answer is that it increases the rate of reaction.