Electrochemistry in Concentrated Hydrochloric Acid (C ≤ 5 M) Progressively Neutralized by Sodium Hydroxide Pellets:  Acid−Base, Oxidation−Reduction, and Solvation Properties of the Medium

Abstract

The acid−base and oxidation−reduction properties of aqueous HCl + NaCl mixtures (HCl + NaCl ≤ 5 M) are characterized by means of the Ro(H) acidity function and the Ro(Cl-) function, which respectively represent their ability to give up the proton and the chloride ion. The electrochemical windows of these mixtures at various working electrodes including mercury drop, carbon, platinum, and gold are determined. The solvation properties of these media are characterized by means of the solvation transfer activity coefficients of the solutes, which are calculated from the normal potential values of the corresponding redox system.

Carbon Paste Electrodes in Facts, Numbers, and Notes: A Review on the Occasion of the 50‐Years Jubilee of Carbon Paste in Electrochemistry and Electroanalysis

“…In the period of 70 s and 80 s, a very diverse electrochemical research with carbon pastes can be illustrated by: i) in vivo monitoring with CPmEs implanted into living animals (e.g., laboratory rat [196] or a monkey [224]), ii) carbon pastes assessed in radiochemistry, either as 14 C-isotope labeled pasting liquid investigated with respect to its miscibility with aqueous solutions [215] or in investigations on the behaviour of synthetic technetium (in the form of Tc(IV) and Tc(VII) ions [225]); iii) protolytic and redox-processes in highly concentrated solutions of HCl þ NaOH [226], or iv) electrocatalytic photolysis of water at a CMCPE [227].…”

“…iv) Africa. Starting from Morocco [295] and Egypt [286,294,300,301], CPEs appear across the continent: in Senegal [326], Cameroon [226], Ethiopia [327], and South Africa [25,328]. v) Asia.…”