The spinodal curve for a binary liquid system is the locus of states for which

Thus it separates regions of stability from instability with respect to liquid/liquid phase splitting. For a given T, there are normally two spinodal compositions (if any). They are the same at a consolute temperature. On curve II of Fig. 14.12 they are a pair of compositions between xα1 and x1β, corresponding to zero curvature.
Suppose a liquid mixture is described by the symmetrical equation
GE/RT = A(T)x1x2
(a) Find an expression for the spinodal compositions as a function of A(T).
(b)Assume that A(T) is the expression used to generate Fig. 14.15. Plot on a single graph the solubility curve and the spinodal curve. Discuss.

Transcribed Image Text:

d2 (&G/RT)-- (const T, P .2 dx 2.4 450 2.2 TK 350 1.8 1.8 250 250 350 450 1