Question

Colloids are purified by:
A.Precipitation
B.Coagulation
C.Dialysis
D.Filtration

Answer 1

Hint: Freshly prepared colloidal solution usually contains the impurities of electrolytes. So it is necessary to purify colloidal solution by removing the impurities of electrolytes present in them.

Complete step by step answer:
Colloid is a phase separate mixture in which one substance of microscopically dispersed insoluble or soluble particles is suspended throughout another substance. Sometimes the dispersed substance alone is called the colloid.
 Precipitation:- Precipitation is any form of liquid or solid water particle that falls from the atmosphere and reaches the surface of earth. Precipitation is caused when a mass of warm, moist air hits a mass of cold air.
Coagulation:- Coagulation also known as clotting, is the process by which blood changes from liquid to a gel, forming a blood clot.
Filtration:- Filtration is the process of separating suspended solid matter from a liquid, by causing the latter to pass through the pores of some substance called a filter. The liquid which has passed through the filter is called the filtrate.
Dialysis:- The process of separating the particles of colloid from those of crystalloid, by means of diffusion through a suitable membrane is called the dialysis. The colloidal particles cannot pass through a parchment or cellophane membrane while the ions of the electrolyte can pass through it.
From the above definition we say that
So the colloids are purified by the dialysis process.

Note:
The electrolytic impurities can be purified by the process of dialysis. Dialysis can be used for removing HCL from the ferric hydroxide solution.Dialysis is the process of separating molecules in solution by the difference in their rates of diffusion through a semipermeable membrane, such as dialysis tubing. Dialysis is also commonly used for buffer exchange and drug binding studies.