Nonquantitative reaction course as a source of errors in titration analysis

Characteristics of nonquantitative reaction course, called "degree course of reaction", known in analytical chemistry literature, have been considered critically. Connection has been ascertained between these characteristics and the criterion (degree) of chemical reaction completeness, widely used in chemical thermodynamics and kinetics, as well as its dimensionless analogue - degree of reaction intensity. It has been shown that different characteristics of reaction course are formed on the basis of various comparison methods for degrees of intensity of a reversible reaction and a hypothetical irreversible reaction of the same stoichiometry in the same conditions. It has been shown that the characteristics of nonquantitative reaction course taken per se, without indication of the method used for finding equivalence point, cannot serve as predictors of errors in titration analysis. The normalized notation of the law of mass action for a generalized reaction has been suggested, which makes it possible to classify reactions on the basis of similarity theory and to facilitate analysis of relationship between criteria of reaction incompleteness and titration degree.