The molar average velocity of the components in a binary mixture in which they are in equimolar counter diffusion is
(a) Equal to mass average velocity
(b) Zero
(c) Always negative
(d) Always positive
I have been asked this question in an interview for job.
My question is taken from Diffusion in a Binary Gas Mixture topic in chapter Diffusion in Solids and Molecular Diffusion in Fluids of Mass Transfer