TOPOLOGICAL ASPECTS OF MOLECULAR-INTERACTIONS IN LIQUID-MIXTURES OF NONELECTROLYTES

It has been shown that activity coefficients of the components of an ( i+j) mixture have a simple topological base and that the same (as well as G(E) (T, x(i)) and H(E) (T, x(i)) data) can be well predicted, on the strength of graph-theoretical arguments when only H(E)(T, x(i) = 0 .4 and 0.5) data for the binary mixture, of almost equal sized compone nts, are available. For (i+j) mixtures that are characterized by the p resence of 1:1 or 1:1 and 1:2 molecular complexes or have components t hat differ appreciably in molar volumes the approach has been modified to well reproduce the activity coefficients data when gamma(i)infinit y datum alone is available for the mixture. The versatility of graph-t heoretical arguments have further been made evident by rationalizing v olumetric and ethalpic effects in (i or i(S) (i.e. i saturated with a salt (S)) (i+j) mixtures to yield worthwhile insight into i) the molec ular state of i and or j (or of the salt S in i and the influence of j on it) and ii) the energetics of molecular interactions that characte rize these mixtures.