What is equimolar counter diffusion?

Equimolar counter diffusion is the phenomenon where two gases, with identical molar masses and at the same pressure, are allowed to diffuse through a solid medium. In this process, molecules of both gases move in opposite directions and mix together without any chemical reaction. Diffusion occurs because gas molecules move randomly and collide with the surrounding medium. As a result, the molecules of one gas can pass through the solid medium while the molecules of the other gas cannot.

The rate of diffusion for both gases is the same in equimolar counter diffusion since they have the same molar masses and diffusion coefficients. Therefore, after a certain amount of time, the concentrations of both gases become equal in the entire volume of the solid medium. Equimolar counter diffusion has various applications in the fields of material science, chemical engineering, and biology. It is used for separation and purification of gases and liquids, and for the study of molecular transport through membranes and tissues.