Question

what are the basic principle behind the action of soaps and detergents

Answer 1

A detergent is a chemical substance you use to break up and remove grease and grime, while soap is simply one kind of detergent. Soap has a long history and was originally made from purely natural products like goat's fat and wood ash. Today, detergents are more likely to be a mixture of synthetic chemicals and additives cooked up in a huge chemical plant and, unlike traditional soap, they're generally liquids rather than solids. Detergents are used in everything from hair shampoo and clothes washing powder to shaving foam and stain removers. The most important ingredients in detergents are chemicals called surfactants—a word made from bits of the words surface active agents.

Answer 2

Most of the dirt is oily in nature and oil does not dissolve in water. The molecule of soap constitutes sodium or potassium salts of long chain carboxylic acids. In the case of soaps, the carbon chain dissolves in oil and the ionic end dissolves in water. Thus the soap molecules form structures called micelles .In micelles, one end is towards the oil droplet and the other end which is the ionic faces outside. Therefore, it forms an emulsion in water and helps in dissolving the dirt when we wash our clothes.

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 towards 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.

Micelles

Soaps And Detergents

In water, the soap molecule is uniquely oriented which helps to keep the hydrocarbon part outside the water.