Showing papers on "Supporting electrolyte published in 1968"

The surface chemistry of kaolinite. I. Surface leaching

Abstract: Aqueous suspensions of kaolinite from Mt. Egerton, Victoria, have been leached at pH 2.25 and 6.0. More ions, in particular aluminium, than predicted from the published cation-exchange capacity have been detected in the leachate. An activation energy of 5 kcal/mole has been calculated for this process of surface leaching. Using a supporting electrolyte of, for example, 10-4M KCl, the electrophoretic mobility of leached and raw clay has been examined as a function of pH, and differences in mobility have been correlated with aluminium removal from the clay surface.

Polarographic Behavior of Tris(2,2′-bipyridine)manganese(II) in Acetonitrile Solutions

Abstract: Polarographic behavior of tris(2,2′-bipyridine)manganese(II) perchlorate at the dropping mercury electrode in acetonitrile solutions has been investigated by the measurement of d.c., a.c. and Kalousek polarograms. The manganese(II) complex gave a five-step reduction wave and a one-step oxidation wave at the dropping mercury electrode when tetraethylammonium perchlorate was used as supporting electrolyte. In the presence of a large concentration of free 2,2′-bipyridine, the limiting currents of the first three steps of the reduction of the manganese(II) complex are all diffusion-controlled and of a one-electron reduction process. The electrode processes for these steps have been concluded to be the reductions to [Mn(bipy)3]+, [Mn(bipy)3] and [Mn(bipy)3]−, respectively.

Electrochemical behavior of platinum in 0.5m hydrochloric acid in the potential range 0.0 to 1.0 volt vs. saturated calomel electrode.

Abstract: Electrochemical reactions of Pt electrode in 0.5 M hydrochloric acid supporting electrolyte in potential range zero to one volt, investigating electrode oxidation

Electrochemical reactions. Part III. The reduction of benzyl bromides at a mercury cathode

Abstract: The half-wave reduction potentials of a series of substituted benzyl bromides show a linear correlation with Hammett σ substituent values with ρ=+0·31 volts. Most benzyl bromides gave the corresponding dibenzylmercury on large scale electroreduction. p-Nitrobenzyl bromide gave 4,4′-dinitrobibenzyl while m-bromo- and 3,4-dichloro-benzyl bromides gave either the dibenzylmercury or the bibenzyl product depending on the supporting electrolyte used. Benzyl radicals are probably formed in the electrochemical rate-determining step.

Cationic Effect on the Polarographic Reduction of Nickel(II) in Acetonitrile

Abstract: The polarographie behavior of nickel(II) acetate salts dissolved in acetonitrile solvent containing small quantities of acetic acid has been investigated in various natures and concentrations of supporting electrolytes. A single reduction wave is observed in the solutions of lithium perchlorate or sodium perchlorate. The limiting current has an intermediate nature of both diffusion- and kinetic controlled polarographic current. A double wave, on the other hand, is observed in the solutions of tetraalkylammonium perchlorate supporting electrolyte such as (CH3)4NClO4, (C2H5)4NClO4 or (n-C4H9)4NClO4. The limiting current of the first step exhibits an intermediate nature of both diffusion and kinetic currents, and that of the second step is kinetic in nature. The effect of the nature and concentration of electrolyte on the visible absorption spectra of acetatonickel(II) complexes in acetonitrile containing small quantities of acetic acid are also discussed. On the basis of evidence, a mechanism which involves...

Polarographic and Voltammetric Studies of Diphenylthiocarbazone and its Chelates with Mercury and Copper in the Ternary Solvent Mixture

Abstract: The solvent extraction method has widely been applied to the analysis of trace elements, particularly in their colorimetric determination. However, in order to apply the extraction method in electroanalytical chemistry, the organic layer containing the extracted sample species has to be evaporated and the residue redissolved in water, or else the sample species must be back-extracted from the organic layer into a suitable aqueous solution.In order to avoid these time-consuming procedures, the present author, with Fujinaga et al., has proposed the use of a ternary solvent mixture, consisting of chloroform, methylcellosolve and water, for the polarographic analysis and has investigated the polarographic behavior of diethyldithiocarbamate in this solvent mixture.The solution for polarographic analysis can be prepared simply by mixing chloroform, into which the sample species has been extracted, with appropriate amounts of methylcellosolve, water and supporting electrolyte. This homogeneous ternary solvent mixture has a dielectric constant high enough to ensure the dissociation of supporting electrolytes.A new cathodic stripping method, depending on the adsorption and subsequent reduction of adsorbed mercuric diethyldithiocarbamate, has been developed in this solvent for the determination of trace amount of mercury.In the preceding report, the polarography of diphenylthiocarbazide in an aqueous solution of 50% methylcellosolve was studied in order to use diphenylthiocarbazide or diphenylthiocarbazone as an organic reagent for the inorganic polarographic analysis. When the concentration of diphenylthiocarbazide was larger than approximately 0.1 mM, two anodic waves could be observed in d.c. polarogram and two corresponding peaks in a.c. polarogram. Since the oxidation of thiol on a platinum electrode occurs at a potential of about + 1.0 V, the electrochemical process of diphenylthiocarbazide at the dropping mercury electrode was confirmed as follows, in acidic media: 2H4Dz-Hg_??_Hg(HDz)2+6H++6e (1)The wave at the more negative potential was an adsorption pre-wave corresponding to the formation of the mercuric complex, Hg(HDz)2, adsorbed on the electrode surface. And in alkaline solution:H4Dz+2OH-_??_H2O+2e (2)H4Dz+Hg+4OH-_??_HgDz+4H2O+4e (3) in which H4Dz, H2Dz and Dz represent diphenylthiocarbazide, diphenylthiocarbazone and diphenylthiocarbodiazone, respectively.As a result of the adsorption of HgDz on the surface of dropping mercury electrode, a minimum was observed at the plateau of the oxidation wave according to equation(2). The total wave was due to the oxidation reaction of equation (3). A similar adsorption wave has been reported for gluthathione, thioglycolic acid, diethyldithiocarbamate, and 2, 3-dimercaptopropanol.In the present paper, the polarographic and voltammetric behaviors of diphenylthiocarbazone and its complexes were investigated in the ternary solvent mixture containing 0.2 M sodium acetate, 0.1 M acetic acid and 0.1 M potassium chloride as the supporting electrolytes.

Ion-exchange evidence for the bipositive mercury(I) ion

Abstract: A technique of ionic-charge determination using an ion-exchange resin in contact with various concentrations of a supporting electrolyte has been used to provide further experimental evidence for the existence of a bipositive charge on the mercury(I) ion in aqueous solution.