Final answer:
When Q is large and at equilibrium with a large Keq, the products have lower free energy than the reactants, indicating that the reaction favors the formation of products.
Step-by-step explanation:
When Q is large, it indicates that the concentration of products is much greater than the concentration of reactants. According to the concept of Gibbs free energy, if Q is greater than K (the equilibrium constant), the reaction will shift to favor the formation of reactants in an effort to reach equilibrium. This shift happens because the system is attempting to lower its Gibbs free energy. However, if the equilibrium constant (Keq) itself is very large, this condition implies that the reaction favors the formation of products at equilibrium, and thus the products will have a lower free energy compared to the reactants.
In conclusion, if Keq is very large, the products have lower free energy than reactants. This means in a system where Q is large and the reaction is at equilibrium with a large Keq, the products would be favored, and they would have a lower free energy than the reactants.