The measurements of density, viscosity and sound speed have been determined by experimental procedures using bicapillary pyknometer, Ostwald’s viscometer and Ultrasonic interferometer respectively. The experimental data related to density, viscosity, sound speed for the system as Urea (aq) and L-Lysine monohydrochloride are further utilized to derive parameters viz. isentropic compressibility (β), apparent molal volume (Φv), apparent molal compressibility (??¤k), intermolecular free length(Lf), Relative association(RA) and Specific acoustic impedance(Z). From these derived parameters we calculate limiting apparent molal volume (??????v °), limiting apparent molal compressibility (??????k °) and experimental slope (Sv * and Sk * ) by using Masson’s equation. The viscosity data are analysed using Jones-Dole equation. The concentration range selected for L-Lysine monohydrochloride is 0.10m to 1.0m. The measurements are conducted at three temperatures viz. 298, 308, 318K. The constancy of temperature is maintained by the use of refrigerated bath with water as circulating medium. The results are interpreted on the basis of solute-solvent and solute-solute interactions where the addition of solute and its concentration produces a major variation on the interactions. This shows the dependency of interactions on the concentration and L-Lysine monohydrochloride behaves as a structure maker in aqueous urea.
