Prediction of viscosity of mixed electrolyte solutions based on the Eyring's absolute rate theory and the equations of Patwardhan and Kumar

The mixing behavior of viscosities of electrolyte solutions at constant ionic strength has been studied for the first time using the Eyring's absolute rate theory and the equations of Patwardhan and Kumar. Coupling of the Eyring's theory with the equations of Patwardhan and Kumar yields simple mixing behavior of viscosities of electrolyte solutions at constant ionic strength, and thus permits the establishment of new simple equations for viscosity, which can provide predictions for mixed solutions using only information on the single solute solutions. The new equations have been compared with the experimental results for fifteen systems and the existing equations reported in literature. The present equations generally give the best predictions and the agreement with experimental results is in general quite good. The effect of different contributions accompanying the mixing process on the predicted results has been studied. The viscosities of the mixed electrolyte solutions can be well predicted only by using the additive contribution from the viscosities of binary solutions at constant ionic strength. The addition of the mixing term in this simple additive equation yields better predictions. The inclusion of the density term has little effect on the predicted results.