. Both soap and detergent are some type of salts. What is the difference between them

Describe in brief the cleansing action of soap. Why do soaps not form lather in hard water? List two problems that arise due to the use of detergents instead. of soaps.


Best Answer

Ans.  A soap is the sodium or potassium salt of a long chain carboxylic acid.


C17H35COO-Na+   Sodium stearate

C15H31COO-Na+   Sodium palmitate

A detergent is ammonium or sulphonate salt of a long chain carboxylic acid.


CH3 - (CH2)11 - C6H4   -SO3- Na+

        CH3 – (CH2)10 – CH2 – SO4 Na+        

Cleansing action of soaps.

Action of soap in  removing an oily spot from a piece of cloth. Most of the dirt particles on skin or clothes are oily in nature, When a dirty cloths is put in water containing dissolved soap, the oil does not dissolve in water. The soap molecules are sodium or potassium salts of long chain carboxylic acids. The acid end of soap dissolves in water while its carbon chain dissolves in the oil. In this way soap molecule form rounded special type of structures called micelles in which one end of the soap molecule is towards the oil droplet while the acid end is towards the water. Soap micelles help in removing the dirt particales from the surface and this dirt dissolves in water and the surface gets cleaned and washed.



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