Thermodynamic properties of hydrochloric acid in mixed solvents: {HCl( mA) + NaCl( mB)} in {(1 − x)H 2O + xd-fructose} at T = (278.15 to 318.15) K

Abstract

The thermodynamic properties of system (HCl + NaCl + C 6H 12O 6 + H 2O) were studied by e.m.f. measurement in the cells without liquid junction: (A) Pt , H 2 ( p = 101.325 kPa ) | HCl ( 0.01000 mol · kg - 1 ) | AgCl – Ag (B) Pt , H 2 ( p = 101.325 kPa ) | HCl ( m ) , C 6 H 12 O 6 ( w ) , H 2 O ( 1 - w ) | AgCl – Ag (C) Pt , H 2 ( p = 101.325 kPa ) | HCl ( m A ) , NaCl ( m B ) , C 6 H 12 O 6 ( w ) , H 2 O ( 1 - w ) | AgCl – Ag At constant total ionic strength (0.5, 1.0, 1.5, and 2.0) mol · kg −1, from (5 to 45) °C, where m A and m B are the molalities of HCl and NaCl, respectively, and w is the mass fraction of fructose in the mixed solvent, which is w = 0.1 during all the measurements. The standard electrode potential of Ag | AgCl in the pure water and mixed solvent has been determined from cells (A) and (B). The activity coefficients lg γ A of HCl in the mixed solvent system have been determined from cell (C).The results show that the activity coefficients of HCl in (HCl + NaCl) solutions still obey Harned’s Rule. The standard transfer Gibbs free energies, entropy and enthalpy of HCl have been calculated. The primary, secondary and total medium effect of HCl have been calculated and discussed.