Final answer:
A negative ΔG' indicates that the reaction proceeds spontaneously in the forward direction, meaning the process happens naturally and favors the formation of products over reactants.
Step-by-step explanation:
If ΔG', also known as Gibbs free energy change, is a negative value, it indicates that the reaction is spontaneous in the forward direction. This means that the process will occur naturally under the given conditions, and it tends to lead towards the products. If ΔG' were positive, it would indicate spontaneity in the reverse direction. When ΔG' is equal to zero, the system is at equilibrium, which suggests there is no net change in the concentrations of reactants and products over time as both forward and reverse reactions occur at the same rate.
The Gibbs free energy equation (ΔG' = -RT ln Keq) provides a quantitative relationship between the standard free energy change (ΔG') and the equilibrium constant (Keq). In the context of an acid-base reaction where Keq = [conjugate base]/[acid], a negative ΔG' would result from a Keq greater than 1, which implies that the products (conjugate base) are favored over the reactants (acid) at equilibrium.
Thus, for the question at hand, if ΔG' is negative, it means that the acid-base reaction proceeds spontaneously towards the formation of conjugate base, indicating option (b) that the reaction is spontaneous in the forward direction is the correct answer.