Explain the mechanism of cleansing action of soap
Answers
Washing up liquid is a kind of soap. Normally, oil and water don't mix, so they separate into two different layers. Soap breaks up the oil into smaller drops, which can mix with the water. It works because soap is made up of molecules with two very different ends. One end of soap molecules love water - they are hydrophilic. The other end of soap molecues hate water - they are hydrophobic.
Hydrophobic ends of soap molecule all attach to the oil. Hydrophilic ends stick out into the water. This causes a drop of oil to form: Soap
These drops of oil are suspended in the water. This is how soap cleans your hands - it causes drops of grease and dirt to be pulled off your hands and suspended in water. These drops are washed away when you rinse your hands.
We know that most of the dirt is oily in nature and oil does not dissolve in water. The molecule of soap or detergent constitutes sodium salts of long chain carboxylic acids. The carbon chain dissolves in oil and the ionic end dissolves in water. Which then makes the soap molecules to surround the dirt and gets rinsed with flowing water.