Question

Which of the following colloids cannot be coagulated easily?
(i) Lyophobic colloids.
(ii) Irreversible colloids.
(iii) Reversible colloids.
(iv) Lyophilic colloids.


NCERT Class XII
Chemistry - Exemplar Problems

Chapter 5. Surface Chemistry

Answer 1

Reversible and lyophilic colloids answer...........

Answer 2

Answer: (iv) Lyophilic colloids.

Explanation: Lyophilic colloids are formed directly by mixing of dispersed phase and dispersion medium. They are quite stable and thus cannot be coagulated easily.

Lyophilic colloids are also called as reversible colloids in nature i.e. they can be reformed if they are precipitated by simple mixing.

Lyophobic colloids can only be formed by special methods and cannot be directly prepared. They are easily precipitated by addition of small amount of electrolyte.

Lyophobic colloids are also called as irreversible colloids in nature i.e. they can not be reformed if they are precipitated by simple mixing.