What is the equation that relates ΔG and reaction quotient Q?

The correct relationship between the Gibbs free energy change (ΔG) and the reaction quotient (Q) is given by the equation ΔG = RTln(Q), particularly in the context of a non-equilibrium state of a reaction. This equation reflects how the free energy change depends on the concentration of reactants and products at any given moment during the reaction, quantified by the reaction quotient Q.

This relationship demonstrates that ΔG will be positive when the reaction is not favorably proceeding forward (often when Q is greater than K, the equilibrium constant), and negative when the reactants are favored (often when Q is less than K). At equilibrium, ΔG equals zero, which aligns with the fact that the system is at a state of balance when Q equals K.

Using this equation allows chemists to understand the thermodynamic favorability of reactions under non-standard conditions. It can also guide the manipulation of concentrations to drive reactions in desired directions, using changes to the reaction quotient to influence the Gibbs free energy change.

In the other provided options, the equations do not accurately reflect the direct relationship between ΔG and Q. For instance, the equation that suggests ΔG = -RTln(Q) misrepresents the direction of spontaneity in relation to