Soaps and detergents info Chemical Man

Soaps and detergents are widely used as cleaning agents. Chemically soaps and detergentsare quite different from each other. The common feature of soaps and detergents is thatwhen dissolved in water the molecules of soap and detergent tend to concentrate at thesurface of the solution or at interface. Therefore, the surface tension of the solution isreduced, it causes foaming of the solution.
Soaps and detergents lower the surface tension of the solution. Such substances are calledsurface-active  agents  or  surfactants.To sum up, soaps and detergents:

1. are used as cleansing agents
2. cause foaming of the solution
3. lower surface tension
4. molecules tend to concentrate near the surface of the solution
5. are the surface active agents
6. are the surfactants
7. can emulsify grease
8. can remove dirt, etc.

Hydrophilic and Lipophilic Parts

Both  soap  and  detergent  molecules  have  two  parts.  One  part  of  the  molecule  is  polar
(ionic) in nature. Polar nature is due to the presence of groups like carboxylate (-COO
–)or sulphonate (-SO3–). The polar group is a hydrophilic group. The hydrophilic group makessoaps and detergents soluble in water. The other part of the soap or detergent molecule isnon polar (nonionic) that is lipophilic. The lipophilic part (a long chain alkyl or a long chainsubstituted aryl group) makes the molecule oil soluble.