ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

The mechanism of hydrogen liberation at mercury electrodes

J. Kůta

Czechoslovak Academy of Sciences, Prague

Abstract: The mechanism of the liberation of H+ caused by the overvoltage at the stable and dropping Hg electrodes was studied. The measurements of the overvoltage of H⁺ were accurate and reproducible on Hg electrodes, especially by the dropping-Hg method which was essentially a polarographic method (I). New overvoltage laws such as the derivation of the logarithmic dependence of overvoltage on the Hg drop time and concn. of acid applied. Polarographic criterions for limiting currents showed by what processes the current was limited. In the case of fast reactions the current was limited by diffusion, but at const. potential it was proportional to t11/6 (t1 = Hg drop time) which corresponded to the diffusion current. If the current was limited by the rate of the reaction, it was proportional to t12/3 and assocd. with the kinetic current. The limiting currents of the weak and irreducible acids behaved as diffusion currents. They decreased after the anions of these acids were added, and simultaneously the half-wave potentials shifted in a neg. direction. In the case of H₃BO₃, the current was of a kinetic nature. A possibility was the detn. from the polarographic data, of the consts. of dissocn. and recombination of weak irreducible acids. 56 references.

Full paper in Portable Document Format: 810a626.pdf (in Czech)

Chemical Papers 8 (10) 626–643 (1954)