Multiple Reactions in a Two-Phase System

Consider a closed system of two phases, I and II, made initially of N°,., moles of k components involved in r reactions, which reaches equilibrium at constant T and P. 

The total number of moles of component i present at equilibrium is  

In other words, in order that the two-phase system be in equilibrium at constant T and P  

Development of the equations of this Section can also be carried out by using Lagrangian multipliers (see, among others, Sandler, 1977). 

Extensionof the findings of Section 12.6.1 to more than three phases, and of 12.6.3 to more than two phases is straightforward (see, for example, Problem 12.51). They are rarely, however, of practical importance. 

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