Ultrasonic studies in dilute solutions of water and nonelectrolytes

Ultrasonic velocities in dilute solutions of water in n-propanol, isopropan ol, glycerol. formamide. N-methyl formamide, dimethyl formamide, tetrahydro furan and propylene glycol have been determined at 238.15 K using single cr ystal variable path interferometer working 3 Mhz. Excess sound velocities h ave been evaluated using the formula which is thermodynamically valid, Both the ultrasonic velocity and excess ultrasonic velocity have bean found to vary nonlinearly with concentration in the high dilution range of water in nonelectrolytes studied. The results are explained by considering the exist ence of water molecules as monomers up to certain optimum concentration (X- 2)(opt) of water and the nonlinear behaviour observed beyond (X-2)(opt) has been explained in the light of water-water and water- nonelectrolyte inter actions leading to the formation of islands of water-nonelectrolyte complex es.