Final answer:
If the standard free energy change (AGº) of a chemical reaction is positive, reactants predominate over products at equilibrium.
Step-by-step explanation:
The standard free energy change (AGº) is a measure of the spontaneity of a chemical reaction under standard conditions. If AGº is positive, it means that the reactants are favored over the products when the reaction is at equilibrium. This indicates that the forward reaction is not spontaneous. Therefore, the correct answer to your question is option B - reactants predominate over products.