scholarly journals The Formation Constants and the Rate Constants of the Electrode Processes of Thiocyanato-Indium(III) Complexes with the Dropping Mercury Electrode

1965 ◽  
Vol 38 (2) ◽  
pp. 234-242 ◽  
Author(s):  
Yoshio Narusawa ◽  
Jinzo Hashimoto ◽  
Hiroshi Hamaguchi
Keyword(s):  
Rate Constants ◽  
Mercury Electrode ◽  
Formation Constants ◽  
Electrode Processes ◽  
Dropping Mercury Electrode

scholarly journals KINETIC MODEL OF THIOUREA DIOXIDE DECOMPOSITION IN AQUEOUS SOLUTIONS OF DIFFERENT ACIDITY

2018 ◽  
Vol 61 (12) ◽  
pp. 87-93
Author(s):  
Yuri V. Polenov ◽  
Gleb A. Shestakov ◽  
Elena V. Egorova
Keyword(s):  
Kinetic Model ◽  
Rate Constants ◽  
Silver Chloride ◽  
Mercury Electrode ◽  
Calculated Data ◽  
Correlation Coefficients ◽  
F Test ◽  
Thiourea Dioxide ◽  
Dropping Mercury Electrode ◽  
The Individual

A stoichiometric mechanism for full thiourea dioxide decomposition in aqueous solution under pH of 4.0 is proposed based on dependences of concentrations of thiourea dioxide and its decomposition products on the time and literature data. The concentration of thiourea dioxide was measured via iodometry, while the intermediates were quantified using the polarography. Polarography was carried out in glass two-electrode electrochemical cell by means of PU-1 polarograph in differential mode. Dropping mercury electrode was used as working one and silver chloride as a reference one. Rate constants for individual stages are obtained via mathematical modeling, presented a system of differential equations. Absolute errors of rate constants, correlation coefficients, and F-factors were also calculated. Verification of supposed kinetic model was conducted using the comparison between experimental and calculated concentrations, F-test and the calculated values of correlation coefficients of the individual stages of the process. Supposed kinetic model of decomposition consists of a number of consequent stages including various compounds such as sulfur monoxide, thiosulfuric, sulfuric, dithionic, hydrosulfuric acids as intermediates was used for previously obtained data for pH of 8.85. To test the universality of supposed model, we simulated kinetics of thiourea dioxide decomposition reaction at pH of 8.85. Experimental kinetic data were taken from literature. The initial approximations of the individual stages constants were taken from previous calculations. Analysis of calculated data: concentration values, F-test, correlation coefficients allowed to conclude about the applicability of proposed mechanism for the process of thiourea dioxide decomposition in a weakly alkaline medium.

Polarography of azobenzene and its p-sulphonic acids

1964 ◽  
Vol 17 (10) ◽  
pp. 1085 ◽  
Author(s):  
TM Florence ◽  
YJ Farrar
Keyword(s):  
Ph Effect ◽  
Aqueous Media ◽  
Mercury Electrode ◽  
Electrode Reaction ◽  
Ammonium Ions ◽  
Current Time ◽  
Electrode Processes ◽  
Ph Values ◽  
Strong Adsorption ◽  
Dropping Mercury Electrode

The behaviour at the dropping mercury electrode of trans-azobenzene and its p-sulphonic acids has been studied by several techniques including d.c., a.c., single sweep, and Kalousek polarography. Current-potential curves recorded at the streaming mercury electrode provided information on the reversibility of the electrode processes, while current-time and electrocapillary curves aided in elucidating the effects of adsorption. The results show that the rate of the electrode reaction of the azo-hydrazo couple is dependent on pH, the minimum rate occurring near pH 9 for azobenzene-4-sulphonic acid in aqueous media. At very low and high pH values, the couple approaches full reversibility at the dropping mercury electrode. This pH effect is apparently due to strong adsorption of both the azo and hydrazo derivatives near the potential of the electrocapillary maximum. Ammonium ions associate with azobenzene-4-sulphonate, and improve the reversibility in intermediate pH regions.

Electrochemical Investigations of the Nickel(II)-Penicillamine System. 2. Direct Identification of Complex Species Involved in Catalytic Nickel Reduction on the Dropping Mercury Electrode

1998 ◽  
Vol 63 (7) ◽  
pp. 995-1006 ◽  
Author(s):  
Florinel G. Banica ◽  
Ana Ion
Keyword(s):  
Mercury Electrode ◽  
Formation Constants ◽  
Active Species ◽  
Electrode Process ◽  
Ligand Complex ◽  
Direct Identification ◽  
Complex Species ◽  
Nickel Ions ◽  
Dropping Mercury Electrode ◽  
System 2

The catalytic polarographic nickel prewave was investigated by making appropriate correlations between prewave current and complex species concentrations as calculated by means of available formation constants. It was concluded that the active species is (D-penicillaminato-N,S)nickel(II) [NiL], whereas the bis-ligand complex, [NiL2]2-, is inert and does not play any role in the electrode process. The catalytic character of the electrode process originates from the regeneration of [NiL] by the reaction of adsorbed ligand molecules with free nickel ions available in the bulk of the solution. Conversely, all the complex species in the Ni2+-cysteine system are labile. Consequently, the reaction mechanism in this case may include the dissociation of the complex [NiL2]2- as an alternative path for the generation of the active species, [NiL]. The bell-shaped form of the prewave was interpreted in terms of potential-dependent catalyst adsorption.

Effect of surface active cations undergoing interfacial rearrangements on deposition type electrode reactions

1988 ◽  
Vol 53 (4) ◽  
pp. 732-742 ◽  
Author(s):  
Anastos Anastopoulos ◽  
Anastasia Christodoulou
Keyword(s):  
Rate Constants ◽  
Mercury Electrode ◽  
Size Ratio ◽  
Inhibition Mechanism ◽  
Electrode Reactions ◽  
Dropping Mercury Electrode ◽  
Surface Active ◽  
Activated Complex ◽  
Effect Of Surface

The influence of the adsorption of methyltriphenyl- and cyclopropyltriphenylphosphonium cations on simple deposition reactions of Cd2+ and Zn2+ at the dropping mercury electrode, is studied by polarographic techniques. The size parameters of the activated complex, r≠, and adsorbate particles, ri, are determined and discussed. It is shown that for substances undergoing interfacial rearrangements, i.e. condensation and reorientation, the values of the size ratio r≠/ri can hardly be correlated to independently determined values of r≠ and ri. Electrode coverages are related to formal rate constants and an elucidation of the inhibition mechanism is attempted.

Sign in / Sign up

Export Citation Format

Share Document