Question

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 1

(i) In multi-molecular colloids, the colloidal particles are an aggregate of atoms or small molecules with a diameter of less than 1 nm. The molecules in the aggregate are held together by van der Waal’s forces of attraction. Examples of such colloids include gold sol and sulphur sol.

(ii) In macro-molecular colloids, the colloidal particles are large molecules having colloidal dimensions. These particles have a high molecular mass. When these particles are dissolved in a liquid, sol is obtained. For example: starch, nylon, cellulose, etc.

(iii) Certain substances tend to behave like normal electrolytes at lower concentrations. However, at higher concentrations, these substances behave as colloidal solutions due to the formation of aggregated particles. Such colloids are called aggregated colloids.

Answer 2

multi-molecular colloids	macro-molecular colloids	Associated colloids
They are formed by the aggregation of a large number of atoms or molecules which generally have diameters less than 1 nm	They are molecules of large size	They are formed by the aggregation of a large number of ions in concentration solution
Example - sols of gold and sulphur	Example - polymers like runner,nylon, strach	Example - soap sol
Their molecular masses are not very high	They have high moleuclar masses	Their molecular masses are generally high
Their atoms or molecules are held together by weak van der Waal's force	Due tolong chain the van der Wall's force holding them are comparatively stronger	Higher is the concentration. greater are the van der Waal's forces.