Question

What are the two classes of emulsions? Give one example of each class. State one activity to test the type of an emulsion.

Answer 1

The two classes of emulsions are oil-in-water (O/W) and water-in-oil (W/O) emulsions. In O/W emulsions, oil is the dispersed phase and water is the dispersion medium, e.g., milk. In W/O emulsions, water is dispersed in oil, e.g., cod liver oil emulsion. To test the type of emulsion, perform the dilution test: add a few drops of water to the emulsion. If it mixes, it is O/W type; if not, it is W/O type.