Emulsions are the colloidal solutions in which both the disperse phase and the dispersion medium are liquids.
Types of emulsions
- Oil-in-water-type emulsions: In this type of emulsions, oil is the dispersed phase and water is the dispersion medium.
- Water-in-oil-type emulsions: In this type of emulsions, water is the dispersed phase and oil is the dispersion medium.
Identification of Emulsions
The following tests can be employed to distinguish between the two types of emulsions.
- Dye test: An oil-soluble dye is added to the given emulsion. If the background becomes colored, the emulsion is water-in-oil type, and if the tiny droplets become colored, the emulsion is oil-in-water type.
- Dilution test: If the emulsion can be diluted with water, this indicates that the emulsion is oil-in-water type. In case the emulsion cannot be diluted with water, it is water-in-oil type.