The polarographic reduction of Bi(III) in the presence of chloride ion

✍ Scribed by H.H. Bauer; P.J. Elving

• Publisher: Elsevier Science
• Year: 1960
• Tongue: English
• Weight: 647 KB
• Volume: 2
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(60)80022-9

✦ Synopsis

The reduction of Bi(II1) to Bi(Hg) at the dropping mercury electrode in 0.5 M perchloric acid solution containing O-0.3 M chloride ion becomes increasingly reversible, generally speaking, as the [Cl-]/pi(III)] ratio increases, as evidenced by changes in various criteria used for determining the "reversibility" of a polarographic electrode process, e.g., the magnitude of the heterogeneous rate constant of the electrochemical reaction (k,), the slope of the d.c. polarogram log plot, and the magnitude of p, the a.c. polarographic efficiency (ratio of the observed and theoretical magnitudes of the faradaic alternating current). The concentration ratio is not, however, the sole determining factor; the absolute concentrations also have an effect. The log plot is apparently a quite inadequate measure of reversibility; k., which is a determining factor in the d.c. polarographic reversibility, is probably not functionally related to the thermodynamic reversibility of the electrode process; p could be a measure of the thermodynamic reversibility of the electrochemical process.