Effect of Temperature on Acid-Base Equilibria

A knowledge of the concentrations of each species in solution is necessary in the elucidation of the chemistry of metal ion complexes with molecules such as EDTA and glutathione. 

The temperature coefiicient of an acid dissociation constant is determined by the enthalpy change of the dissociation reaction, and is given by the thermodynamic relation 

The standard enthalpy change AH° varies with temperature according to 

FIGURE 3-3 Variation of ionization constants with temperature. All values are on the molal scale. Data from Handbook of Chemistry and Physics 53d ed., p. D-121, Chemicai Rubber, Cleveland, OMo, 1972-1973.) 

The equilibrium between the acid form In of an indicator In and the alkaline form Iob may be written 

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