The dielectric constants of some aqueous-organic solvent mixtures have
been analysed by an equation analogous to Grunberg and Nissan equatio
n. The hydration numbers are found out at the maxima and minima of the
plots of Delta epsilon versus x(2) The extent of hydration of organic
solvents is discussed in the light of structure of the solvents. It i
s shown that the equations can be very well applied to aqueous-organic
solvent mixtures. An interaction parameter d is defined to fil the di
electric constant data of the mixtures which bears a linear relationsh
ip with epsilon(2).