125.

Explain the following term:
(i) Electro-dialysis
(ii) Phases of a colloidal solution.

Answer:

(i) It is a process in which colloidal solution is purified under influence of electric-field. The colloidal solution containing ionic impurities is put in a bag of parchment paper under electric field so that ions pass through parchment paper but colloidal solution does not.



(ii) Colloidal solution is heterogeneous which consists of two phases, the dispersed phase and dispersion medium.
(a) Dispersed phase. It is the component which is present in small amount and consists of particles (1 to 100 nm). It may be solid, liquid or gas.
(b) Dispersion medium. The medium in which colloidal particles are dispersed is called dispersion medium. It may also be solid, liquid or gas.