Aqueous Solutions Of Alkali Metal Salts Research Articles

New aspects of the electrochemistry of heteropolyacids: Part III. Further proof of minimal solvation and ion pairing of silicotungstic and phosphotungstic species in acidic concentrated aqueous solutions of alkali-metal salts

New aspects of the electrochemistry of heteropolyacids: Part III. Further proof of minimal solvation and ion pairing of silicotungstic and phosphotungstic species in acidic concentrated aqueous solutions of alkali-metal salts

NMR relaxation data on the microstructure of aqueous solutions of alkali-metal salts and hydroxides

Nuclear relaxation rates have been measured for deuterium, sodium, rubidium, and cesium in aqueous solutions of alkali-metal bromides, sulfates, and hydroxides. A method previously developed has been used to calculate the ionic coordination numbers and to estimate the mobilities of the water molecules in various zones. The temperature dependence of the relaxation rate for the deuterons has been used in estimating the activation energies for reorientation of water molecules around the various ions. It is necessary to use an ion-pair model to explain the results for solutions of carbonates, sulfates, and hydroxides.

The equivalent conductivity of aqueous solutions of alkali metal salts of a number of ionic polysaccharides.

Measurements of the equivalent conductivity of aqueous solutions of alkalimetal salts of a number of ionic polysaccharides at 25 degrees C are reported. The polysaccharides studied are: (1) three carboxymethylcelluloses of various degrees of substitution (Li+, Na+, Cs+ salts) in the concentration range 4 X 10(-4) - 6 X 10(-2) equivalents alkali ion per liter, (2) Polypectate (Li+, Na+, K+, Cs+ salts) in the range 1.5 X 10(-4) - 2 X 10(-2) equivalent alkali ion per liter, and (3) Dextransulfate (Li+, Na+, K+ salts) in the range 3 X 10(-4) - 10(-1) equivalent alkali ion per liter. The results are compared to some earlier data and to a limiting law for conductance of rod-like polyions derived by Manning. It is concluded that although qualitative agreement is obtained between observed data and the limiting law when various polyions of different charge densities are compared at a given concentration, the concentration dependence predicted by the limiting law is in agreement with the observed curves only for polyions of a relatively low charge density. At higher charge densities appreciable deviations occur, and dextransulfate which does not have the rod-like polyion structure required by theory does not conform to the predicted concentration dependence at all.

Determination of Ion Activity Coefficients from the Measurement of Membrane Concentration Potentials–Activity Behavior of Alkali-metal Cations in Aqueous Solutions at 25°C

Abstract The membrane concentration potentials across a permselective sulfonated polystyrene collodion-base membrane were measured with aqueous solutions of alkali-metal salts at 25.0°C. By assuming the ideal behavior of the membrane, the activity coefficients of the critical cations were determined from the membrane concentration potentials at ionic strengths higher than 0.01. The ion activity coefficients of alkali-metal cations were found to follow the order Li+>Na+>K+ for the chlorides, nitrates, perchlorates, and sulfates. The order of activity coefficients of Na+ in different halide solutions was bromide>chloride>fluoride. Considerable differences were observed between the individual and mean activity coefficients at ionic strengths higher than 0.01. The individual ion activity coefficients determined from the experimental data were analysed by means of the extended Debye-Hückel eauation.