Question

Coagulation of lyophilic sol is done by

• A. addition of suitable electrolyte
• B. addition of suitable solvent like alcohol, acetone, etc.
• C. Both (a) and (b)
• D. None of the above

Answer 1

The correct option is C Both (a) and (b)

Lyophilic colloids coagulate hardly due to its stablility.
Factor responsible for the stability of lyophilic sol is
1. Charge of colloidal particles
2. Solvation of colloidal particles

Thus, to coagulate the lyophilic sol, its stability should be removed.

Addition of suitable electrolyte will remove the stability due to charged colloidal particle.

Lyophilic colloids coagulate hardly by the addition of electrolyte due to protective layer of dispersion medium.

Therefore, an suitable solvent should be added to remove the solvation of sol.

In case of hydrophilic sols, we need to add dehydrating agent in addition to electrolyte to remove the hydration of sol.