Polarographic determination of hydrogen ion activities in strongly acidic media: a new acidity function

1972 ◽  
Vol 68 (0) ◽  
pp. 1656 ◽  
Author(s):  
Jiří Janata ◽  
Geertje Jansen
Keyword(s):  
Hydrogen Ion ◽  
Polarographic Determination ◽  
Acidity Function ◽  
Acidic Media ◽  
Ion Activities

Polarographic determination of hydrogen ion activities

1973 ◽  
Vol 44 (1) ◽  
pp. 137-143 ◽  
Author(s):  
Jiři Janata ◽  
Raymond D. Holtby-Brown
Keyword(s):  
Hydrogen Ion ◽  
Polarographic Determination ◽  
Ion Activities

scholarly journals DIFFERENTIAL PULSE POLAROGRAPHIC DETERMINATION OF ARSENIC IN BITUMINOUS COAL

1998 ◽  
Vol 6 (7) ◽  
pp. 27-32
Author(s):  
M. Nogami Eurica ◽  
M. Dalmeida Gracinda ◽  
Jorge Nozaki
Keyword(s):  
Coal Sample ◽  
Bituminous Coal ◽  
Supporting Electrolyte ◽  
Arsenic Concentration ◽  
Differential Pulse ◽  
Polarographic Determination ◽  
Differential Pulse Polarography ◽  
Acidic Media ◽  
Pulse Polarography

Differential pulse polarography was employed for the determination of arsenic in bituminous coal from Figueiras, Parana, Brazil. The dried coal sample was crushed to -100 mesh, ashed, and treated with reducing reagents in acidic media. The arsine generated was collected and selectively oxidized to Al +3 using an absorbing solution of 0.1 mol.L -1 [tris(hydroxymethyl) aminomethane] ( TRIS) and 0. 002 mol.L -1 silver nitrate. A solution of TRIS and hydrochloric acid, pH -1, was used as supporting electrolyte for differential pulse polarographic determination of Al+3 in the concentration range 0.05 -0.60 μglmL. The average arsenic concentration found was 69.0 ± 2.6 mg.kg -1 and was in agreement with the spectrophotometric method using silver-diethyldithiocarbamate-pyridine.

Aqueous trifluoroacetic acid as a medium for organic reactions. I. Acidity functions and the identity of the manganese(VII) species found in powerfully acidic media

1976 ◽  
Vol 54 (3) ◽  
pp. 440-447 ◽  
Author(s):  
Udo A. Spitzer ◽  
Trevor W. Toone ◽  
Ross Stewart
Keyword(s):  
Trifluoroacetic Acid ◽  
Water System ◽  
Visible Spectrum ◽  
Pair Formation ◽  
Acidity Function ◽  
Acidic Media ◽  
Uv Visible ◽  
Acidity Functions ◽  
Trifluoroacetate Complex

The HR acidity function has been determined for the trifluoroacetic acid–water system, and extended beyond 100% acid by the addition of trifluoroacetic anhydride, to 99.5 wt.% anhydride. The existing H0 acidity function is corrected and extended to 100% trifluoroacetic acid, confirming Eaborn's observation that H0 attains a minimum value at approximately 97% acid. Comparison of the acidity functions shows that although trifluoroacetic acid is only weakly protonating, it is a strongly protonating-dehydrating medium. Changes in the uv–visible spectrum of potassium permanganate produced by changing acid concentration are used to calculate the degree of further ionization of the permanganate ion; the correlation of this with the HR acidity function further suggests the presence of the permanganyl cation, MnO3+, or its trifluoroacetate complex or ester, MnO3•O2CCF3, in these solutions. A cryoscopic investigation into the mode of ionization of permanganate in trifluoroacetic acid reveals that extensive ion-pair formation occurs in this solvent. Although this effect prevents an unequivocal determination of the number of solute particles being made the results are consistent with the presence of a permanganyl species in solution.

Determination of hydrogen ion activities in various ternary water/methanol/dioxane solvent systems

1985 ◽  
Vol 173 ◽  
pp. 281-288 ◽  
Author(s):  
G. Papanastasiou ◽  
I. Ziogas ◽  
D. Jannakoudakis
Keyword(s):  
Hydrogen Ion ◽  
Ion Activities ◽  
Solvent Systems
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