leaving the negatively charged carboxylate end exposed on the grease surface. At the Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Orientation of dissolved soap at waterg–grease interface Dirt particles embedded i a film of grease Suspended grease particles floated away from grease surface Highly polar carboxylate end soluble in water Nonpolar hydrocarbon end insoluble in water Na + Na + Grease XII U15 Chemistry in XII U15 Chemistry in - - - - same time the negatively charged carboxylate groups are strongly attracted by water, thus leading to the formation of small droplets called micelles and grease is floated away from the solid object. When the water is rinsed away, the grease goes with it. As a result, the cloth gets free from dirt and the droplets are washed away with water.
The micelles do not combine into large drops because their surfaces are all negatively charged and repel each other. The cleansing ability of a soap depends upon its tendency to act as a emulsifying agent between water and water insoluble greases. . .
Detergents: Synthetic detergents are formulated products containing either sodium salts of alkyl hydrogen sulphates or sodium salts of long chain alkyl benzene sulphonic acids. There are three types of detergents. Detergent Type Example Anionic detergent Sodium Lauryl sulphate (SLS) Na + S O - Cationic detergent n-hexadecyltrimethyl ammonium chloride N + Cl - N , N , N -trimethylhexadecan- -aminium chloride Non-ionic detergent Pentaerythrityl stearate. CH OH CH OH CH OH -hydroxy- , -bis(hydroxymethyl)propyl heptanoate Detergents are superior to soaps as they can be used even in hard water and in acidic conditions.
The cleansing action of detergents are similar to the cleansing action of soaps.