EXPERIMENTAL-DETERMINATION OF THE ASSOCIA TION CONSTANT OF MERCUROUS ION WITH CHLORIDE IN AQUEOUS-SOLUTIONS AT 20-80-DEGREES-C

The constant of association of mercurous (I) ion with chloride in aque ous solutions was determined by solubility of calomel and potentiometr ic titration with Pt and liquid mercury electrodes. It was shown that calomel (Hg2Cl2) is not involved in the reaction of disproportionation in acidic medium in the solubility experiments. The strong complexati on of Hg-2(2+) ions in chloride solutions prevents the precipitation o f the solid phase. In the range of 20-80 degrees C for reaction: Hg-2( 2+)(aq) + 2Cl(-)(aq) = Hg2Cl20(aq) the following equation was obtained : lg K-0(t,degrees C) = 13,95 - 0,07492 . t = 4.875.10(-4) . t(2) - 8, 33.10(-7). t(3) The free energy, of formation of Hg2Cl20(aq) complex a t 25 degrees C was found: -179,399 kJ/mol. In the range of 10-100 degr ees C the following temperature dependence of calomel was recommended: pL(t,degrees C) = 19,289 - 6,230.10(-2). t+1,44.10(-4). t(2)