Polarography with Alternating Currents. V. A.C. Polarography of Some Common Anions

Abstract

The A.C. polarography of Cl^-, Br^-, CNS^-, OH^-, SO₃^-, CN^-, and S^- is discussed. Chloride, bromide, hydroxide, and sulphide ions were estimated quantitatively by A.C. polarography in suitable supporting electrolytes.

The anodic A.C. waves present the following characteristic features:

(i) They are asymmetric and much sharper than the usual cathodic A.C. waves

(ii) The summit potentials do not correspond to the relative half-step potentials but occur at voltages correspondmg to the commencement of the anodic discharge.

(iii) In contrast to cathodic A.C. polarography the anodic A.C. electrode processes strongly interfere with one another, the wave helght of a given anion species is greatly reduced in the presence of anions dischargeable at more negative potentials.