Standard electrode potentials in molten chlorides—II

Abstract

The electrode potentials of the system Ag(I)/Ag(0) in molten magnesium chloride—potassium chloride (32·5:67·5 mol-%) at 475°C are reported to obey to Nernst equation. Using this as a reference, (apparent) standard electrode potentials for the systems Mn(II)/Mn(0), Zn(II)/Zn(0), Tl(I)/Tl(0), Cd(II)/Cd(0), Cr(II)/Cr(0), Fe(II)/Fe(0), Sn(II)/Sn(0), Pb(II)/Pb(0), Co(II)/Co(0), Ni(II)/Ni(0), Cu(I)/Cu(0), Sb(III)/Sb(0), Pd(II)/Pd(0), Pt(II)/Pt(0) and Au(I)/Au(0) have been determined. In all cases plots of electrode potential vs logarithm of solute mole-fraction are rectilinear and their slopes agree within a few mV with the calculated value of the Nernst slope (2·303 RT/nF). On the mole-fraction scale the (apparent) standard electrode potentials for the above systems are −1·2078, −0·9262, −0·7554, −0·7168, −0·6546, −0·5364, −0·4836, −0·4836, −0·4780, −0·3601, −0·1673, −0·1495, −0·0594, 0·3867, 0·5802 and 0·8519 V vs unit mole-fraction silver reference, respectively.