The densities, rho, ultrasonic speeds, u and viscosities, eta of l-arginine and l-histidine in aqueous-sodium salicylate (1% and 2% sodium salicylate in water, w/w) solvents were measured at temperatures (293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K and at atmospheric pressure in seven different concentrations. The experimental density data have been used to calculate the apparent molar volume, V-phi, limiting apparent molar volume, V-phi degrees and transfer volume, V-phi,V-tr degrees. Likewise from the ultrasonic speed data, different thermo-acoustical parameters, such as apparentmolar compressibility, K-s,K-phi, limiting apparentmolar compressibility, K-s,K-phi degrees and transfer compressibility, K-s,K-phi,K- tr degrees have been evaluated. The viscosity data have been used to determine Falkenhagen Coefficient, A, Jones-Dole coefficient, B, free energy of activation of viscous flow per mole of solvent, Delta mu(1)degrees(#) and solute, Delta mu(2)degrees(#), entropies, Delta S degrees(#) and enthalpies, Delta H degrees(#) of activation of viscous flow. These parameters have been discussed in light of solute-solute and solute-solvent interactions prevailing in these solutions and their variations are revealed to get the basic picture of the molecular interactions occurring in the systems studied. The negative values of dB/dT favour structuremaking behavior of amino acids in aqueous solutions of sodiumsalicylate. The free energy parameters indicate the formation of transition state in the presence of amino acids. (C) 2020 Elsevier B.V. All rights reserved.
