Steady-State Molecular Diffusion in Liquids

Your objectives in studying this section are to be able to  

Calculate molar fluxes during steady-state molecular, one-dimensional diffusion in liquids. 

Calculate molar fluxes for steady-state diffusion of A through stagnant B, and for equimolar counterdiffusion, both in the liquid phase. 

The integration of equation (1-70) to put it in the form of equation (1-77) requires the assumption that DAB and c are constant. This is satisfactory for gas mixtures but not in the case of liquids, where both may vary considerably with concentration. Nevertheless, it is customary to use equation (1-77) to predict molecular diffusion in liquids with an average c, and the best average value of DAB available. Equation (1-77) is conveniently written for dilute solutions as 

For this case, NA = const, NB - 0, PA = 1 then equation (1-96) becomes 

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Example 1.19 Steady-State Molecular Diffusion in Liquids... 

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