Question

Give two examples of emulsifying agents for $O/W$ and $W/O$ types of emulsions.

Answer 1

Hint: To give examples for $O/W$ and $W/O$ types of emulsions we must first know what an emulsion is. An emulsion is a mixture of two or more liquids that are usually immiscible which means they do not mix or are unblendable due to liquid-liquid phase- separation. Emulsions are part of a more general class of two-phase systems of matter which are known as colloids.

Complete step-by-step answer:As we know emulsions are liquid-liquid colloidal systems which means dispersion of finely divided droplets in another liquid.
An emulgent or which is also called an emulsifying agent which is used for stabilization of an emulsion which is easily soluble in water is likely to be used in an oil-in-water emulsion than water-in-oil which is the main difference between the two.
Emulsions can be classified into two types: oil in water emulsions and water in oil emulsions.
a.Oil in water emulsions - oil is the dispersed phase that is distributed into the continuous phase or also called as dispersion medium which is water.
b.Water in oil emulsions – water acts as the dispersed phase and oil is the dispersion medium.
Two examples of oil in water emulsions are proteins and synthetic soaps.
Two examples of water in oil emulsions are long chain alcohols and fatty acids like butter.

Note:Emulsions of oil in water are unstable and sometimes they separate into two layers on standing in such cases an emulsifier or an emulgent Is added. An emulsifier is a substance that stabilizes an emulsion by increasing its kinetic stability. Emulsifiers are part of a group of compounds which is known as surfactants or surface active agents. Some examples of emulgent are egg yolk, sodium stearoyl lactylate, sodium phosphates.