If the natural log is taken on both sides of the disequilibrium ratio and both sides is multiplied by RT, one obtains:
However,  is the standard free energy, so that  is the free energy of the reaction.
This shows that the free energy of a reaction is just an alternative way of expressing the disequilibrium ratio and as such gives a more intuitive interpretation of free energy. That is if the free energy for a reaction is less than zero then it indicates that  and hence , i.e the net reaction rate is from left to right.