The anodic oxidation of the borohydride ion in alkaline aqueous solution at various metal electrodes has been investigated by the charging-curve-oscillographic technique. Only at platinum is the ionization of hydrogen unequivocally confirmed, although there is evidence that it can occur at palladium and nickel and indications of a reaction proceeding at mercury. Provided that the concentration of potassium borohydride is not too low in comparison with that of the supporting electrolyte (potassinm hydroxide), hydrogen ionization is the sole electrochemical reaction. The effects of varying pH, current density and borohydride ion concentration on the reaction potential have been studied. Electrolytic poisons completely inhibit the ionization. Decay curves following prolonged anodic polarization in both concentrated and dilute solutions are shown and explained.
R~sum~--A l'aide d'une technique oscillographique, on a examin6 l'oxydation anodique de l'ion borohydride en solution alkaline aqueuse avec plusieurs 61ectrodes metalliques. Une ionisation de l'hydrog~ne ne peut 6tre confirm6e qu'avec l'61ectrode de platine. I1 y a des preuves qu'une ionisation de l'hydrog~ne se produit 6galement aux electrodes de palladium et de nickel et des indices qu'une r6action a lieu h l'61ectrode de mercure.
Zusammenfassung--Mit Hilfe einer oscillographischen Technik wurde anodische Oxydation des Borhydrid-ions in w~isserig alkalischer L6sung an verschiedenen Metallelektroden untersucht.