Fowler and Guggenheims quasi-chemical model of the solution

Fowler and Guggenheim s quasi-chemical model of the solution 

Let us look again at our binary solution formed of the two components A and B. The exchange energy is given by Wab This time, this energy is sufficient to influence the distribution of the atoms, which, therefore, is no longer random. 

The quasi-chemical model of a solution postulates the existence of a true thermod5mamic equilibrium between one pair A-A, one pair B-B and two pairs A-B, as follows  

Such an equilibrium is known as a quasi-chemical equilibrium. 

We will ply the law of mass action to that equilibrium, supposing that the species A-A, B-B and A-B constitute a perfect solution. 

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