The majority of the soil is oily, and dirt will not dissolve in water. Soap is made up of sodium and potassium salts of long-chain carboxylic acids. The carbon chain in soap dissolves in oil, while the ionic end dissolves in water. As a result, micelles are formed by the soap molecules. One end of a micelle faces the oil droplet, while the other end, which is the ionic, faces the outside. As a result, when we wash our clothing, it creates an emulsion in water and aids in the dissolution of soil.
Soap is a kind of molecule in which both the ends have different properties.
- Hydrophilic end
- Hydrophobic end
The first one is the hydrophilic end which dissolves water and is attracted to it whereas the second one is the hydrophobic end that is dissolved in hydrocarbons and is water repulsive in nature. If on the surface of the water, soap is present then the hydrophobic tail which is not soluble in water will align along the water surface. The soap molecule is oriented differently in water, that helps to hold the hydrocarbon component out of the water. As clusters of molecules form, the hydrophobic tail arises from the interior of the cluster and the ionic end emerges from the cluster’s surface, forming a micelle. When soap is in the form of micelles, it is capable of cleaning the oily dirt that accumulates in the centre. These micelles continue to exist as colloidal solutions. As a result, the dirt on the fabric is quickly removed. The soap solution appears cloudy as it forms a colloidal solution which scatters light.