Question

Define electro-osmosis and illustrate it diagrammatically.

Answer 1

Electro-osmosis is defined as the movement of the dispersion medium under the influence of an electric field when the movement of colloidal particles is prevented by a semipermeable membrane. In this process, the dispersion medium moves towards the oppositely charged electrode while colloidal particles are blocked by the membrane. The process is demonstrated by an apparatus where a colloidal solution is placed between semipermeable membranes, and upon applying an electric current, the water level rises on one side and falls on the other.

Diagrammatically, it can be shown as two compartments separated by semipermeable membranes with electrodes on the outside; the dispersion medium moves through the membranes under the applied electric field while colloidal particles are restricted.