What are micelles? how it is formed? & Explain the process of removal of dirts by soaps & detergents.

Micelle: When soap is added to water, then the fatty acid ions aggregate to form spherical clustures which are called as micelles. They are forme during cleasing action of soap or detergent when they areused with water.

Mechanism Of Micelle formation: Micelles are prepared during the cleasing action of soaps and also known as associated colloids. These micelle behaves as electrolyte at low concentration and as colloid at higher concentrations

  • Actually the Soap is a sodium salt of a long chain fatty acid in which the fatty acid ion is made of polar head soluble in water and and a long zig zag non polar hydrocarbon chain. In the aqueos solution soap ionizes as RCOO- and Na+ ions.

  • The micelle are formed only above a partcular temperature called Kraft Temperature Tk and above a particular concentration known as Critical micelle concentration (CMC) which is found to be 10-3 mol/L for soaps.
  • when soap is adde to water, the fattty acid ionizes to give RCOO- and Na+ ions. In the critical concentration, the polar water soluble get attracted towards water while the non polar tails attract each other.
  • Hence, the ions aggregate to form spherical clustures which are called micelle. The core of a micelle is made up of non polar tails dissolved together and the water soluble polar heads ponts outward.
  • since the similar micelle repel each other so they remain suspended in water.


Process of removal of dirt: When a dirty cloth is washed with soap and water,  the non-polar grease film on the fabric dissolves in the non-polar core of micelle And so when washed with water both the dirt and micelles are washed away.


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When soap molecules are present in water, the molecules arrange themselves in the form of a cluster in such a manner that their hydrophobic ends are away from the water molecules, and their hydrophilic or ionic ends are towards the water molecules (as shown in the following figure). This is known as micelle formation and the cluster that is formed is called a micelle.
Hope it is clear to you.
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A micelle is a spherical aggregate of soap molecules in water. In other words, they are clusters of soap molecules. Micelles are formed when soap or detergent is dissolved in water.

Soap (also detergent) molecules have two ends, hydrophobic and hydrophyllic. The characteristics of Hydrophobic ends are non-polar, water repelling and dirt attracting. They are made up of hydrocarbons and stick on the dirt. The characteristics of Hydrophyllic ends are polar, water attracting, ionic. These are made up of ions of metals like sodium, potassium, etc. They attract water. When force is applied on the dirt, these hydrophobic end which are stuck on the dirt, pull it, removing the dirt from the material.

This is how soaps and detergents remove dirt.

Hope this helps u........

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