Application of photoacoustic calorimetry to the determination of volume changes in reactions involving radical anions in aqueous solutions

摘要

The particular features of the application of photoacoustic calorimetry to the determination of volume changes in reactions involving radical anions in aqueous solutions are addressed. Analysis of recent literature data on volume changes of redox pairs, including our previous results on the couples NO_2-/NO_2 and SO_4~(2-)/SO_4~(·-), together with known values of molal changes for ionization reactions, allow us to derive an empirical correlation for these categories of reactions. Finally, the pertinence of describing the volume changes of complex processes as a simple sum of separable terms is critically examined.