Temperature Dependence of the Formation Constant of Thiocyanatopentaaquochromium (III) in Acidic Solution.

摘要

The equilibrium constants for the ionization of carboxylic acids in water pass through a maximum as temperature changes. If the equilibrium constant represents a one-step process, then the attendant thermodynamic properties such as enthalpy and entropy are also temperature dependent. Blandamer and co-workers in the United Kingdom and Canada have recently concluded that the ionization of the carboxylic acids is a multistage process and the temperature dependence of the observed equilibrium constant can be fit by combination of the equilibrium constants of the individual steps, each such equilibrium constant having temperature-independent enthalpy. Blandamer and his co-workers also derived an expression to test the temperature dependence of the enthalpy.