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.

The correct answer is option B.

Explanation:

When we increase number of molecules of reactant frequency of the molecular collision increases due to which effective collision between reactant molecules to form a product also increases, With this overall rate of the reaction increases.

Where as:

When we increase the temperature of the reactant molecules increase in average kinetic energy of the molecules is observed.

When we increase the activation energy of the reaction rate of the reaction slows down,