Standard Potential at 25° C. of the Silver–Silver Chloride Electrode in Formamide

FORMAMIDE is a very good solvent for many strong and medium weak acids. In order to determine their dissociation constants accurately by potentiometric measurements it is necessary to know the standard potential of a reference electrode with respect to the normal hydrogen electrode. Until recently, only the value of the cadmium–cadmium chloride electrode has been given in the literature 1 . We have been able to determine the standard potential of the silver–silver chloride electrode by the classical method using the following cell without liquid–liquid junction : Pt, H 2 /HCl(HCONH 2 )/AgCl, Ag Platinum electrodes were prepared according to Jones 2 and the silver–silver chloride electrodes by the electrolytic method 3,4 . (Both types of electrodes were reproducible within 0.5 mV.)