NaCl-KCl 50-50 mole

An important drawback of LiCl-KCl eutectic as a solvent is the hygroscopic nature of LiCl. In the case of molten equimolar NaCl-KCl both components are relatively nonhygroscopic however, the liquidus temperature of this mixture is -- 300 C higher than that of LiCl-KCl eutectic. The solvent can be prepared by mixing reagent-grade salts and then dried under vacuum at 400-500 0 for several hours. The melts can be further purified by preelectrolysis or by the same treatment as used for the LiCl-KCl eutectic. Another method involves the use of highly purified NaCl and KCl (vacuum sublimation at 750°C).  

A standard potential series has been established primarily by Flengas and co-workers in this solvent over the temperature range 700-900 0. Oombes et reinvestigated the redox couples Ag+/Ag, Au+/Au, 

Oo2+/Oo, Ou+/Ou, Ni2+/Ni, Pb /Pb, Pd +ZPd, Pf /Pt, Sn /Sn, and Zn +/Zn. The electroactive species were introduced by coulometric oxidation of the metal rather than by adding the anhydrous chlorides. The results are in substantial agreement with those obtained by Flengas and coworkers. 

The reduction mechanism of Or has been studied by Oho and Ku-roda. The chronopotentiograms showed a two-step reduction apparently involving a one-electron step followed by a two-electron step. Only the first step was found to be a diffusion-controlled process. The diffusion coefficient of Or + was reported. 

The diffusion coefficient for Fe + was reported by Kornilov et A well-defined one-step chronopotentiogram was obtained by adding FeCls to the melt. Dubinin et showed that Fe + was generated by 

---