Os. Pokrovsky, EXPERIMENTAL-DETERMINATION OF THE ASSOCIA TION CONSTANT OF MERCUROUS ION WITH CHLORIDE IN AQUEOUS-SOLUTIONS AT 20-80-DEGREES-C, Geohimia, (6), 1995, pp. 881-894
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)