Margules Equations and Non-ideal, Asymmetric Solutions

Because most real solutions do not follow the parabolic, symmetrical form of the two-suffix Margules equations, it is necessary to add more flexibility to the equations by adding more coefficients and more terms. One way to do this is to simply define a second Wq term of the type in (15.22), then combine the two Wq terms in a linear equation in X. This can be imagined as the mixing of two solutions, each symmetrical but having different IPg s  

Now mix X2 moles of the first solution with Xi(= 1 — X2) moles of the second, stir well, and make a new solution, which is described by the sum of (15.31) and (15.32)  

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