Final answer:
The products of an exergonic reaction have the lowest level of free energy compared to the reactants or the transition state. The reaction releases energy and occurs spontaneously once the positive activation energy barrier is overcome.
Step-by-step explanation:
The lowest level of free energy in an exergonic reaction would be found at the point where the reaction's products are formed. An exergonic reaction is one that releases free energy (negative ΔG), indicating that the products of the reaction have less free energy than the reactants. This release of energy is what makes the reaction spontaneous; however, this does not mean it happens immediately but rather without the input of additional energy. The activation energy for the reaction, which is the energy required to initiate the reaction, is always positive, as it represents the energy barrier that must be overcome for the reaction to proceed. Once this energy barrier is surmounted, the reaction continues spontaneously as the system moves toward the state with the lowest possible energy. Unlike the transition state of the reaction, which exists at a higher energy level than the reactants, the products are lower in energy than both the reactants and the transition state.