Abstract
The activity coefficient of ethanol-water solution, the concentration of which is determined by measurement of the change of height and surface area of curvature of its meniscus, was obtained by unsteady static means using Stefan''s vertical capillary tube especially at room temperature where equivalent vapor pressure is low.
The activity coefficient was calculated by Eq. (12) deduced from Stefan-Maxwell equation (1) and its value agreed with that obtained by distillation in steady state.
