Ionic Equilibria of Picric Acid in Mixed Anphiprotic Solvents.The 2-Methoxyethanol/Water Solvent System.

Picric acld Is the gulde solute used In our studies In order to verify the applicability of an emplrikal treatment that descrlbes the dependence of the dlssoclatlon constant on temperature and composltlon of the solvent mlxture ( x Is mole fractlon).The 2-methoxyethano/water solvent system has been employed In thls work operatlng at 19 temperatures ranging from -10 to +80 °C; by use of the conductometric method the dissociation constant values of plcrlc acld have been evaluated by the Fuoss-Hsla equation. The data have been fltted by three emplrlcal equations that represent the functlons K = K(T), K = K ( x ) , and K = K(T,x). The K = K(T,x) equatlon In Its complete form Is composed of 20 terms, someof whkh can be elhnlnated because of small statistkal weigt; the number and type of these terms vary on passlng from one solvent system to another, and the best-flttlng form, which In thls case represents 13 terms, Is suggested. The posslblllty of extrapolatlng K values of plcrk acM In a pure water solutlon Is lnvestlgated and compared wlth similar previous calculatlons.