Binary solvent mixtures were prepared by mixing a required volume of PhNO2 and CH3NO2 with earlier conversion of required mass of each liquid into volume at 298.15 K using experimental densities. A stock solution for each salt was prepared by mass and the working solutions were obtained by mass dilution. The density (q) was measured by means of vibrating-tube Anton Paar density-meter (DMA 4500M) with a precision of 0.0005 g/cm3 . It was calibrated by double-distilled water and dry air. Solvent viscosities were measured by means of a suspended Ubbelohde-type viscometer, calibrated at 298.15 K with doubly distilled water and purified methanol using density and viscosity values from the literature [6–8]