When soap is dissolved in water it forms a colloidal suspension in water in which the soap molecules cluster together to form sphereical micelles. In a soap micelle, the soap molecules are arranged
radially with hydrocarbon ends directed towards the centre and ionic ends directed outwards. (The ionic ends are directed outwards because negative charges at the ends repel one another).
When a dirty cloth is put in water containing dissolved soap, then the dydrocarbon ends molecules in the micelle attache to the oil or grease particles present on the surface of dirty cloth. In this way the soap micelle entraps the oily or greasy particles by using its hydrocarbon ends. the ionic ends of the soap molecules in the micelles, however remain attached to water. When the dirty cloth is agitated in soap solutioin, the oily and greasy particles present on its surface and entrapped by soap micelles get dipersed in water due to which the soap water becomes dirty but the cloth gets cleaned. The cloth is cleaned throughly by rinsing in clean water a number of times.
