METHOD OF DETERMINING EQUILIBRIUM CONSTANTS OF REACTIONS OF LOW-SOLUBLE SALTS WITH SOLUBLE COMPLEX COMPOUNDS

摘要

FIELD: physicochemical methods.;SUBSTANCE: invention relates to determining various thermodynamic constants for inorganic and organic substances in theoretic and applied chemistry fields. Method includes individual potentiometric titration, in the course of which water is added to achieve limiting degree of the extent of reaction owing to change in the coefficient of dilution at invariable concentration of titrant until potential jump comes to end. Coefficient of dilution is calculated according to formula: f = (V₁+V₂+V₃)/V₄, where V₁, V₂, V₃ represent volumes of metal salt solution, water, and titrant, respectively, and V₄ represents initial volume of substance in question. Concentration of this substance is calculated taking into consideration coefficient of dilution. From this concentration, molar solubility of low-soluble salt or equilibrium concentration of soluble complex compound in the stoichiometric point is calculated, after which equilibrium constant is found taking into consideration stoichiometric coefficients.;EFFECT: accelerated determination and increased information validity thereof.;5 tbl, 2 ex