Thermoelectric power of potassium chloride with reversible electrodes

Abstract

Measurements have been made of the thermoelectric power of the cell Pt | C, H₂+ HCl | KCl | H₂+ HCl, C | Pt using both pure KCl and KCl crystals doped with SrCl₂. The use of this system, in which the electrodes are reversible to Cl^–, permits an unambiguous evaluation of the individual heats of transport for potassium and chloride ions. The results of this determination show that both Q_M and Q_X are slightly larger than the corresponding enthalpies of migration. The accuracy with which Q_MX=Q_M+Q_X, and either Q_M or Q_X, may be determined is limited by uncertainties concerning the vacancy concentrations in KCl and, to a lesser extent, by our incomplete knowledge of transport numbers and the value of the non-configurational part of the entropy of formation of an anion vacancy .