Apparent molar volumes, V 2 , φ , and viscosities, η, of glycine, dl-α-alanine, dl-α-amino-n-butyric acid, l-leucine, and l-phenylalanine in water and in (0.5, 1.0, 2.0, 4.0, and 5.5) mol·kg-1 aqueous sodium acetate solutions have been determined at 298.15 K from densities and flow time measurements, respectively. The standard partial molar volumes, V ∞ 2, obtained from V 2 , φ , have been used to calculate the corresponding volume of transfer at infinite dilution, Δt V ∞ , from water to aqueous sodium acetate solutions. B coefficients have been calculated using the Jones−Dole equation. The side-chain contributions to V ∞ 2 and B coefficients have been calculated. The comparison of Δt V ∞ values with the literature shows that the effect of the acetate ion follows the same order as in the Hofmeister series.

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Densities, F, of glycine, DL-R-alanine, DL-R-amino-n-butyric acid, L-valine, and L-leucine in aqueous and in mixed aqueous solutions of zinc chloride, (0.1, 0.5, 1.0, and 1.5) mol • kg -1 , have been determined by using a vibrating-tube digital densimeter at (288.15, 298.15, 308.15, and 318.15) K. These data have been used to calculate the apparent molar volumes, V 2,φ , of the studied amino acids. The partial molar volumes, V 2 0 , at infinite dilution are evaluated and further used to obtain the corresponding transfer volumes, ∆ t V 0 for amino acids from water to aqueous zinc chloride solutions. Partial molar expansibilities, V 0 E , hydration numbers, n H , interaction coefficients, and side chain group contributions of amino acids have also been calculated. The ∆ t V 0 values for the studied amino acids are positive, and these values increase with an increase in the concentration of zinc chloride as well as with temperature. The parameters obtained from the volumetric study are used to understand various mixing effects due to the interactions between amino acids and zinc chloride in aqueous solutions.