(N/A) The existence of charge on colloidal particles is confirmed by the electrophoresis experiment. When an electric potential is applied across two platinum electrodes dipping in a colloidal solution,the colloidal particles move towards one or the other electrode. The movement of colloidal particles under an applied electric potential is called electrophoresis.
Positively charged particles move towards the cathode,while negatively charged particles move towards the anode. This can be demonstrated by the experimental setup shown in the figure.
When electrophoresis,i.e.,the movement of particles,is prevented by some suitable means,it is observed that the dispersion medium begins to move in an electric field. This phenomenon is termed electroosmosis.