Question

Migration of sol particles under influence of electrical field is known as _______ .
1. electrophoresis
2. field effect
3. electrolysis
4. none of the above

Choose the correct option

Answer 1

Electrical Properties (Electrophoresis): The particles of the colloids are electrically charged and carry positive or negative charge. The dispersion medium has an equal and opposite charge making the system neutral as a whole. Due to similar nature of the charge carried by the particles, they repel each other and do not combine to form bigger particles.

That is why, a sol is stable and particles do not settle down. Arsenious sulphide, gold, silver and platinum particles in their respective colloidal sols are negatively charged while particles of ferric hydroxide, aluminium hydroxide are positively charged. The existence of the electric charge is shown by the phenomenon of electrophoresis.

It involves the 'movement of colloidal particles either towards the cathode or anode, under the influence of the electric field' depending on charge of the particles.