Question

What are the characteristics of the following colloids? Give one example of each
(i) Multimolecular colloids (ii) Lyophobic sols (iii) Emulsions

Answer 1

1. They are formed by the aggregate of a large number of atoms or molecules which generally have diameters less than 1 nm, e.g., sols of gold, sulphur etc.

2. Lyophobic sols: These sols are usually formed by the inorganic materials like metals, their sulphides etc.They are irreversible in nature i.e. once precipitated cannot return the colloidal sol by simply addition of the dispersion medium.

3. Emulsions: An emulsion is a mixture of two or more liquids that are normally immiscible. There are two basic types of emulsions: oil-in-water (O/W) and water-in-oil (W/O). In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include vinaigrette, milk, mayonnaise.