The Thermodynamics of Redistribution Reactions

If there is no enthalpy change, the equilibrium position will be governed by the TAS term, and Kt for a two-site exchange shown in Eqs. (6)-(7) will 

Moedritzer (2) has pointed out that a very rough measure of AH° can be obtained from measurement of K at just one temperature since 

The difference AG°ob8erved — AG°nnd m s the driving force of the reaction, thus 

Equation (14) assumes that the difference between the measured and statistical AG° is due solely to the AH0 contribution and that AS0 does not differ appreciably between statistical and nonstatistical exchange. It has been pointed out (5) that such an approximation will be very poor when 

AG°ohgerv d AG°I.in lom is less than 1-2 kcal/mol since differences in molecular solvation and aggregation in solution could lead to A5° values 0. 

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