FATTY ACIDS

1. They are monocarboxylic organic acids (R.COOH) having a hydrocarbon chain of 4 - 30 carbon atoms.
2. The polar carboxylic group is hydrophilic (Gk. hydro - water, phillic - to love) or water soluble.
3. The remaining part of fatty acid, that is hydrocarbon chain is however nonpolar, hydrophobic (Gk. hydro - water, phobes- fear) or water insoluble.
4. It is soluble in fat solvents and is, therefore, lipophilic.
5. Substances like fatty acids which have both hydrophilic and hydrophobic components are called amphipathic.
6. Fatty acids reduce surface tension of water; increase its wetting power and hence capacity to clean. Soap action in due to this phenomenon.
7. Depending upon the absence or presence of double bonds, fatty acids are of two types-

(i) Saturated                    (ii) Unsaturated