question_answer 20)

 What is the difference between multimolecular and macromolecular colloids? Give one example of each. How are associated colloids different from these two types of colloids?

Answer:

The main points of distinction are:

	Multimolecular colloids	Macromolecular colloids
1.	The particle size is less than that of colloidal range	The particle size Falls in the colloidal range
2.	They existas aggregate of smaller panicles.	These are already macromolecules in nature.
3.	These are mostly lyophobic colloids.	These are mostly lyophilic colloids.

Colloidal sol of sulphur is an example of multimolecular colloid while colloidal sol of starch represents macromolecular colloid. Difference between associated colloids, multimolecular and macromolecular colloids. Multimolecular colloids are formed by the aggregation of a large number of simple molecules, macromolecular colloids consists of macromolecules having size in the colloidal range. On the other hand, associated colloids also called micelles, are generally electrolytes. They exist as ions at low concentration. However, above a particular concentration called critical micelle concentration (CMC) and above a particular temperature called Kraft temperature , these get associated and exhibit colloidal behaviour. Soap is a common example of associated colloids.