The polarographic hydrogen wave of hydrochloric acid in non-aqueous methanolic sohrtions shifts towards less negative potentials in presence of traces of triphenylphosphine, -arsine and -stibine. Tbe three additives exert a catalytic effect on the hydrogen-evolution reaction. This character has been hitherto ascribed to organo-nitrogen and -sulphur compounds only.
Differences in the behaviour of the additives are noted which point to corresponding disparities in the extent, type and mechanism of their adsorption on the surface of the eIectrode.
R&sum&La vague polarographique del'hydrogene del'aclde chiorhydrique en solutions non-aqueuses de methanol se d6plac.e vers des potentiels plus ntgatifs en pr&ence de traces de triph&ryIphosphineamine et -stibine. Ces trois additifs exercent un effet catalytique sur la reaction d'evolution de l'hydrogene. Ce caracthre a 6tt jusqu'ici uniquement assignC a I'azote organique et aux composb sulfures.
On note des dilX5rence.s darts le ccmportement des additifs, qui induisent a conclure B des disparitbs correspondantes dans les vaieurs, les types et lea m&anismes de leurs adsorptions a la surface de l'electrode.
Zusammenfassung-Die polarographische Wasserstoffwelle von HCI in nichtw;isserigen methanolisthen Lasungen verschiebt in Gegenwart von Spuren von Triphenylphosphin, -arsin und stibin gegen negativere Potentiale. Die drei Zusatzstoffe haben eine katalytische