Please explain cleansing  action of soap and detergents

• Soaps are cleansing agents capable of reacting with water and dislodging the unwanted particles from clothes or skin.
• The molecules of soap are sodium or potassium salts of long chain carboxylic acids.
• A soap molecule has a tadpole shaped structure.
• At one end (long non-polar end) of soap molecule is a hydrocarbon chain which is insoluble in water but soluble in oil.
• At the other end (short polar end) of soap molecule, there is a carboxylate ion which is hydrophilic i.e. water soluble but insoluble in oil.

 

 

 

• Soap on mixing with water forms a concentrated solution and causes foaming.
• The long non-polar end of soap gravitates towards and surrounds the dirt and absorbs the dust in it.
• The short polar end with the carboxylate ion repels the water away from the dirt.
• A spherical aggregate of soap molecules is formed in the soap solution in water, and is called a micelle.
• Thus, the soap molecule dissolves the dirt and our clothes get clean.

 

Answered by Ramandeep | 14th May, 2018, 10:07: AM