VISCOSITY OF NAI SOLUTIONS IN WATER-TERT-BUTANOL MIXTURES AT 35-DEGREES-C AND 40-DEGREES-C

Viscosity of water-tert-butanol mixtures and of NaI solutions in those mixtures at 35 and 40 degrees C have been measured. Results are discu ssed in terms of the effect of alcohol on the water structure and of N aI on the structure of water-alcohol mixtures. Temperature coefficient s of viscosity have been calculated for several water-alcohol and wate r-amide mixtures. We conclude that it is precarious to describe struct ures basing on Delta eta/Delta t values. It can be only presumed that whatever structure of solution arises, it is unstable when its tempera ture coefficient of viscosity is large. Plots of relative viscosities of NaI solutions (at various concentration of NaI) in water-tert-butan ol mixtures have minima at about 6 mol% alcohol i.e. the composition r ange in which water structure exhibits the maximum ordering effect by tert-butanol molecules. A comparison of viscosities and standard solut ions enthalpies for NaI solutions in water-alcohol and water-amide sys tems is made.