Surface Concentrations and Compound Formation in Aqueous Sulfuric Acid

1994 ◽  
Vol 47 (1) ◽  
pp. 91 ◽  
Author(s):  
LF Phillips
Keyword(s):  
Sulfuric Acid ◽  
Acid Solution ◽  
Equilibrium Constants ◽  
Free Water ◽  
Acid Strength ◽  
Water Vapour Pressure ◽  
Water Molecules ◽  
Compound Formation ◽  
Enthalpy Changes ◽  
Rate Of Reaction

The concentration of free water molecules at the surface of a strong sulfuric acid solution is found to be very low, mainly as a consequence of the formation of acid hydrates. Values of equilibrium constants and enthalpy changes for successive hydration reactions of H2SO4 have been calculated from the variation of water vapour pressure with acid strength and temperature. The results support the conclusion of Fried et al. that the rate of reaction of a molecule such as N2O5 with a sulfuric acid aerosol is controlled by the rate at which the molecule can penetrate into the bulk of the liquid.

scholarly journals Solvent extraction of Sc(III) from sulfuric acid solution by bis(2-ethylhexyl) phosphonic acid in toluene

2002 ◽  
Vol 67 (4) ◽  
pp. 265-272 ◽  
Author(s):  
Devendra Koladkar ◽  
Purshottam Dhadke
Keyword(s):  
Sulfuric Acid ◽  
Acid Solution ◽  
Sulfuric Acid Solution ◽  
Equilibrium Constants ◽  
Phosphinic Acid ◽  
Extraction Equilibrium ◽  
H2so4 Concentration ◽  
Liquid Liquid Extraction ◽  
Extraction Reaction ◽  
Reaction Proceeds

Liquid-liquid extraction of scandium(III) from sulfuric acid solution using bis(2-ethylhexyl) phosphinic acid (PIA-8) in toluene has been studied. The extraction of scandium(III) was found to be quantitative with 0.03 M PIA-8 in toluene in the acidic range of 0.1?0.5 M and 6.0?8.0 M H2SO4. The effect of the reagent concentration and other parameters on the extraction of scandium(III) was also studied. The stoichiometry of the extracted species of scandium(III) was determined on the basis of the slope analysis method. The extraction reaction proceeds via the cation exchange mechanism in the H2SO4 concentration range of 0.1?0.5M and the extracted species is ScR3.3HR. However, at higher acidity (6.0M?8.0M H2SO4) it proceeds by solvation. The extracted species is HSc(SO4)2.4HR. The temperature dependencies of the extraction equilibrium constants were examined to estimate the apparent thermodynamic functions (?H, ?S and ?G) for the extraction reaction.

Equilibria in complexes of N-heterocyclic molecules. XVII. Covalent hydration and the rate of dissociation of the Bis(2,2':6',2'-terpyridyl)iron(III) ion in acid solution

1978 ◽  
Vol 31 (9) ◽  
pp. 1959 ◽  
Author(s):  
WS Walters ◽  
RD Gillard ◽  
PA Williams
Keyword(s):  
Sulfuric Acid ◽  
Acid Solution ◽  
Dissociation Process ◽  
Heterocyclic Molecules ◽  
Essential Step ◽  
Aqueous Sulfuric Acid ◽  
Rate Of Reaction

The dissociation of Fe(tpy)23+ has been studied in aqueous sulfuric acid. The rate of reaction increases upon addition of small amounts of acid, reaches a maximum, and then falls to zero in a complex fashion as the acid approaches limiting concentration, and aH2O falls to zero. No dissociation occurs in the absence of water, and it is evident that covalent hydration of the complex is an essential step in the dissociation process.

Temperature and concentration dependence of equivalent conductivity in Ca(NO3)2-CaI2-H2O system

1980 ◽  
Vol 45 (6) ◽  
pp. 1639-1645 ◽  
Author(s):  
Jindřich Novák ◽  
Ivo Sláma
Keyword(s):  
Linear Function ◽  
Concentration Dependence ◽  
Mole Fraction ◽  
Constant Temperature ◽  
Salt Concentration ◽  
Free Water ◽  
Water Molecules ◽  
Equivalent Conductivity ◽  
Calcium Salts ◽  
Fraction I

The dependence of the equivalent conductivity on the temperature and composition of the Ca(NO3)2-CaI2-H2O system was studied. The ionic fraction [I-]/([I-] + [NO-3]) was changed from 0.1 to 0.5, the mole fraction of calcium salts (assumed in anhydrous form in the presence of free water molecules) was 0.075-0.200. The equivalent conductivity was found to be a linear function of the ionic fraction at constant temperature and salt concentration.

Fundamental Measurements of the Friction on an Atomically-Flat Terrace of Au(100) in Sulfuric Acid Solution under Potential Control Using Electrochemical Atomic Force Microscope

2006 ◽  
Vol 512 ◽  
pp. 395-398
Author(s):  
Nobumitsu Hirai ◽  
Tatsuya Tooyama ◽  
Toshihiro Tanaka
Keyword(s):  
Aqueous Solution ◽  
Sulfuric Acid ◽  
Silicon Nitride ◽  
Acid Solution ◽  
Atomic Force Microscope ◽  
Friction Force ◽  
Potential Range ◽  
Potential Control ◽  
Atomic Force ◽  
Atomically Flat

Potential dependence of the friction force between an atomically-flat terrace of Au(100) single crystal and a tip attached to a silicon nitride cantilever of electrochemical atomic force microscope (EC-AFM) have been investigated qualitatively in 0.05 M H2SO4 aqueous solution. It is found that the friction force gains when the potential increases in the potential range between −400 mV and 400 mV vs Hg/Hg2SO4 electrode.

scholarly journals Continuos Operation of Chromium (VI) Recovery from Sulfuric Acid Solution by Liquid Surfactant Membrane.

1991 ◽  
Vol 17 (6) ◽  
pp. 1104-1109 ◽  
Author(s):  
Yasushige Mori ◽  
Shingo Hibin ◽  
Hideyuki Uemae ◽  
Masataka Tanigaki ◽  
Wataru Eguchi
Keyword(s):  
Sulfuric Acid ◽  
Acid Solution ◽  
Sulfuric Acid Solution ◽  
Chromium Vi
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