Differentiate between the following (a) Multimolecular colloids and macromolecular colloids (b) Coagulation and peptisation (c) Activity and selectivity of catalyst.

Multimolecular colloid and Macromolecular Colloid:

In multimolecular colloids,the colloidal particles consist of aggregates of atoms or small molecules with diameters less than 1nm.For example-A gold sol,sulphur sol In macromolecular type of colloids,the dispersed particles are themselves large molecules(usually polymers like protein and starch).Since these molecules have dimensions comparable to those of colloidal particles,their dispersions are called macromolecular colloids.For example-most of lyophilic sols belong to this category.