Final answer:
The Arrhenius equation demonstrates that an increase in activation energy results in a decrease in a reaction's rate, making the statement true.
Step-by-step explanation:
The Arrhenius equation expresses the relationship between the rate of a chemical reaction and its activation energy (Ea). According to this equation, which is written as k = Ae-Ea/RT, the rate constant (k) decreases as the activation energy increases, assuming that the temperature (T) remains constant. Therefore, the statement that as a reaction's activation energy increases, the rate of the reaction decreases is true. When the activation energy is high, fewer reactant molecules will have the energy needed to overcome the energy barrier and react, leading to a slower reaction rate.