This work is concerned with the study of solute-solvent interaction of amino acids: [DL-Valine, DL-Methionine and L-Arginine] as solutes in water and in hydrochloric acid solution (0.1 mol.L.−1) as solvents. This study covered experimental measurements of partial molal volume from precise density measurements using Anton Paar (DMA 60/602) densimeter, as well as theoretical calculations concerning partial molal volume, and some related parameters, a comparison and discussion was made in the light of these measurements. Measurements of the dynamic viscosities of amino acids solutions have been done over concentration variation from (0.04-0.2 mol.L.−1) at four temperatures in the range of (293.15-308.15)K. The resulting data have been utilized to verity the validity of Jones and Dole equation, and the viscous behaviour of the systems have been interpreted with regard to the contributions of the various viscosity components and the arrangements of solvent molecules. It was found that B-coefficient of amino acids in this study flow the order: Methionine >Valine > Arginine > This study clarifies that each of B-Coefficient, Partial Molal Volume, Van der Waal’s Volume and Effective Flow Volume can be considerd as parameters to account for solute-solvent interaction

Potentiostatic polarization and weight loss methods have been used to investigate the corrosion behavior of carbon steel in sodium chloride solution at different concentrations (0.1, 0.4 and 0.6) M under the influence of temperatures ( 293, 298, 303, 308 and 313) K. The inhibition efficiency of the amoxicillin drug on carbon steel in 0.6 M NaCl has also been studied based on concentration and temperature. The corrosion rate showed that all salt concentrations ( NaCl solution) resulted in corrosion of carbon steel in varying ratio and 0.6 M of salt solution was the highest rate (50.46 g/m².d). The results also indicate that the rate of corrosion increases at a temperature of 313 K.. Potentiodynamic polarization studies showed that the examined inhibitor suppress both anodic and cathodic process and behave as mixed type inhibitor. The adsorption of amoxicillin was found to obey Langmuir isotherm model. Arrhenius equation and transition state theory were used to calculate kinetic and thermodynamic parameter. Results obtained showed that corrosion reaction of carbon steel in NaCl is spontaneous and there is a good agreement between the data got from the both techniques employed. SEM analysis was performed to study the film persistency of the inhibitor.