Abstract
Following previous studies on solid metals, electrocapillary measurements are reported for the adsorption of a series of heterocyclic and aromatic bases (and their ions) at the mercury electrode. The adsorption isotherms are derived for various electrode potentials and standard electrochemical free energies Δ G ° of adsorption are deduced and related to molecular and electronic structure of the adsorbates. Specific π-orbital interaction effects are indicated which determine the orientation of the bases at the electrode. It is shown that dipole interaction effects lead to variations of Δ G ° (adsorption) with the 3/2 power of surface coverage θ; this prediction is confirmed experimentally. The variation of Δ G ° with θ 3/2 has two distinct linear regions, the change of slope (∂Δ G °/∂θ 3 2 ) E being related to molecular orientation at high fields and coverages. The effects are closely related to the shifts of the potential of the electrocapillary maximum (e.c.m.) observed in the solutions of the bases. The observed Δ G ° values at the e.c.m. are related to those found for adsorption of two bases at the air/water interface.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
