THERMODYNAMICS OF THE AMALGAM CELL BAR-LI2SO4(M)-VERTICAL-BAR-HG2SO4-VERTICAL-BAR-HG) IN WATER, (METHANOL PLUS WATER), AND (ACETONITRILE PLUS WATER) SOLVENT MIXTURES

The electromotive force E of the amalgam cell {LixHg1-x \ Li2SO4(m) \ Hg2SO4 \ Hg} has been measured as a function of the mole fraction x of Li metal in amalgams, and of the molality m of Li2SO4 in (methanol water) and (acetonitrile + water) solvent mixtures containing up to 0. 3 mass fraction of the organic component, at the temperature 298.15 K. The respective standard electromotive forces EO, have been determined together with the relevant activity coefficients gamma(+/-) as a func tion of Li2SO4 molality. A new scheme is introduced here and implement ed for verification of the internal consistency of the gamma(+/-) resu lts in terms of complementary pairs of concentration cells with transf erence. The E-m(o) depends linearly on the mass fraction w of the orga nic component of the solvent mixture within the range explored, accord ing to: E-m(o)/V = 2.80137 - 0.20325w(methanol), E-m(o)/V = 2.80137 - 0.23139w(acetonitrile), which reproduce the observed E-m(o) values to within +/-0.2 mV. (C) 1998 Academic Press.