Standard Aqueous Potentials for the Thallium Amalgam Electrode and for the Thallium Amalgam/Thallous Chloride Electrode from 283.15 to 328.15 K and for the Thallium Electrode and for the Thallium/Thallous Chloride Electrode from 288.15 to 308.15 K, and Thermodynamic Solubility Product for the Thallous Chloride from 283.15 to 328.15 K

From e.m.f. measurements of the cells: Pt/TlxHg1-x/TlCl, aq, m = 0.002 mol kg-1/AgCl/Ag/Pt, and Pt/TlxHg1-x/TlCl/KCl, aq, m = 0.5 mol kg-1/AgCl/Ag/Pt, from 283.15 to 328.15 K, the standard potentials of the thallium-amalgam electrode and of the thallium-amalgam/thallous-chloride electrode have been determined, and can be represented by equations: ETl + Hgo V = 0.2621201 - 2.356183 × 10-3( T K) + 1.646874 × 10-6( T K)2, and ETlCl + Hgo V = -0.5998551 + 0.001106567( T K) - 2.842696 × 10-6( T K)2. The thermodynamic solubility product of thallous chloride has been obtained therefrom over the same temperature range, and can be represented by: R ln Ks = 79.6845 - 1.98518 × 104( T K)-1 - 0.103259( T K). The logarithm of the rational activity coefficient of Tl in dilute amalgams is a linear function of the mole fraction of thallium: log10fTl = Qx, where in turn Q is a linear function of temperature: Q = 0.33976 - 0.066533( T K). Combining the present results with recent literature data for thallium concentration cells, the standard potentials of the thallium electrode and of the thallium/thallous-chloride electrode have been redetermined from 288.15 to 308.15 K, and can be expressed by: ETlo V = 0.1949595 - 2.110302 × 10-3( T K) + 1.204957 × 10-6( T K)2, and ETlClo V = -0.5323660 + 4.484192 × 10-4( T K) - 1.768069 × 10-6( T K)2, respectively. The standard thermodynamic functions at 298.15 K for the thallium amalgamation reaction and for the species TlCl(s), TlCl(aq), Tl+(aq), and thallium amalgam have finally been obtained.