When the concentration of reactant molecules is increased

Complete question is;

When the concentrations of reactant molecules are increased, the rate of reaction increases. The best explanation for this phenomenon is that as the reactant concentration increases,

A)the average kinetic energy of molecules increases.

B)the frequency of molecular collisions increases.

C)the rate constant increases.

D)the activation energy increases.

E)the order of reaction increases.

B) The frequency of molecular collisions increases.

Explanation:

When we increase number of reactant molecules, the effective collision between the reactant molecules will form a product which also increases. As a result, the overall rate of the reaction will also increase which means the frequency of the molecular collision will also increase as well.

Thus, the correct answer is Option B