Question

Match the List-I with List-II and select the correct answer using the codes given below the lists.

List I	List II
A. Coagulation	1. Scattering
B. Lyophilization	2. Washing of precipitates
C. Peptization	3. Purification of colloids
D. Tyndall effect	4. Electrolyte

• A. A-4; B-3; C-2; D-1
• B. A-2; B-1; C-3; D-4
• C. A-3; B-1; C-2; D-4
• D. A-4; B-3; C-1; D-2

Answer 1

Answer: (A)

A-4; B-3; C-2; D-1

(A) Addition of an electrolyte causes coagulation as a result of the preferential adsorption of the ions of charge opposite to that on the colloidal particle.

(B) Lyophilization is a method of purification of colloids. Other methods include dialysis, ultrafiltration, and ultracentrifugation.

(C) Peptization is the process by which a coagulated precipitate is returned to its colloidal state. eptization can be minimized by washing a precipitate with a solution of an electrolyte that is volatilized during an ensuing drying step.

(D) Tyndall effect is light scattering by particles in a colloid or in a very fine suspension.