EXTRAPOLATION OF MOLAR EQUILIBRIUM-CONSTANTS TO ZERO TONIC STRENGTH AND PARAMETERS DEPENDENT ON IT, COPPER(II), NICKEL(II), HYDROGEN(I) COMPLEXES WITH GLYCINATE ION AND CALCIUM(II), HYDROGEN(I) COMPLEXES WITH NITRILOTRIACETATE ION

The stability constants of the complexes of glycinate ion with copper( II), nickel(II) and hydrogen(I) and of nitrilotriacetate ion with calc ium(II) and hydrogen(I) and the ionic product of water (K-w) were dete rmined potentiometrically. The measurements were carried out at 25.0 d egrees C in four different ionic strengths up to I (=I-c)=2.50 and two different ionic media (KNO3 and (CH3)(4)NNO3). Extrapolation of equil ibrium constants to zero ionic strength and ionic strength corrections to equilibrium constants were carried out with the data obtained from both media using the TEC (thermodynamic equilibrium constant) equatio n and computer program. The constants of the potassium complexes with nitrilotriacetic acid at low ionic strength are also given. Successful attempts to predict equilibrium constants for other ionic media using TEC parameters and the procedure of the specific ion-interaction theo ry (SIT) are given. The variations of equilibrium constants with the i onic strengths and ionic media are demonstrated.