A student investigates the rate of reaction between calcium carbonate and dilute hydrochloric acid at two different temperatures, T1 T_1\,T1 and T2T_2T2, where T2>T1T_2 > T_1T2>T1. The Maxwell-Boltzmann distribution curves for the reactant molecules at these temperatures are shown below.
Which of the following statements best explains, on a molecular level, why the reaction rate is significantly higher at T2 T_2\,T2 than at T1T_1T1?
The activation energy, EaE_{\text{a}}Ea, is reduced at T2T_2T2, lowering the energy barrier for the reaction.
The collision frequency doubles because the average kinetic energy of the particles doubles.
A much greater fraction of the reactant molecules possess energy equal to or greater than the activation energy, EaE_{\text{a}}Ea.
The peak of the distribution shifts to the right, meaning the most probable kinetic energy exceeds the activation energy, EaE_{\text{a}}Ea.