Hydration and Determination of Hydrodynamic Radii of Zinc Sulphate Heptahydrate: A Viscometric and Conductometric Study

The viscosity and conductivity data of zinc sulphate heptahydrate are measured at temperature 303K and 308K in aqueous solution over the concentration range 0.1 moldm-3 to 1.0 moldm-3. The variation in viscosity with the molarity of the salt in water depicts nature of hydration of ions taking place in three different regions low concentration region, middle concentration region and higher concentration region of solution. The value of dissociation constant (Kc), degree of dissociation (α), molar conductivity at infinite dilution ( ) and hydrodynamic radii (r) have been calculated at both the temperatures. Results indicated that hydrophilic interactions are dominant in the hydration process of zinc sulphate heptahydrate followed by the formation of hydrated ion-pairs surrounded by the water molecules.