Again, consider a regular solid solution of components A and B. Prove that, under the right circumstances, plots of Gmix versus mole fraction X will have two points of inflection, symmetrically located at 1/2RT XB = 2V.
Be sure to carefully describe and defend your choice of "the right circumstances".
5. Yet again, consider a regular solid solution of components A and B. Find an expression for the critical temperature above which there is complete miscibility of A and B, i.e., above which there is no solvus.