Question

Match the following:

Property	Statement	Application/discover
(i) Tyndall effect	(a) Due to unequal bombardment by solvent molecules	1. Sewage disposal
(ii) Coagulation	(b) Surface area is large	2. Smoke precipitator
(iii) Brownian movement	(c) Movement of colloidal particles under the influence of electric field	3. Ultramicroscope
(iv) Adsorption	(d) Due to neutralisation of charge	(4) Ice cream
(v) Electrphoresis	(e) Due to scattering of light	(5) Colloidal medicines
(vi) Stability	(f) Addition of protective colloid	(6) Robert Brown

Answer 1

(i) Tyndall effect is light scattering by particles in a colloid or in a very fine suspension. Tyndall effect is useful to distinguish colloidal solution from the true solution.

(ii) Coagulation is a process which involves coming together of colloidal particles so as to change into large sized particles which ultimately settle as a precipitate or float on the surface. Chemical coagulation is an essential part of drinking water and wastewater treatment. In drinking water, it is used for the clarification of water, using coagulant agents mainly for municipal water treatment.

(iii)Brownian movement is the random motion of particles suspended in a fluid resulting from their collision with the fast-moving molecules in the fluid. Scottish botanist Robert Brown discovered Brownian

movement

(iv) Adsorption is the capability of all solid substances to attract to their surfaces molecules of gases or solutions with which they are in contact. The adsorption of food items like ice cream is an exxample.

(v) Electrphoresis is the movement of colloidal particles under the influence of electric field. Electrophoresis is a technique used to separate DNA fragments according to their size using ultramicroscope.

(vi) Stability increases as the surface area increases.