Final answer:
The best way to find where a reaction becomes spontaneous is by comparing the enthalpy (ΔH) and the entropy (ΔS) changes of the reaction, according to the Gibbs free energy equation.
Step-by-step explanation:
To determine where a reaction becomes spontaneous, you should compare the enthalpy change (ΔH) and the entropy change (ΔS) of the reaction. These two properties are components of the Gibbs free energy equation, ΔG = ΔH - TΔS, where ΔG represents the Gibbs free energy change, T is the absolute temperature in Kelvin, ΔH is the change in enthalpy, and ΔS is the entropy change. The spontaneity of a reaction at a specific temperature can be determined by setting ΔG to zero and solving for T, which would give you the temperature at which the reaction is at equilibrium. The appropriated answer to the option provided is B) By comparing ΔH and ΔS.