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

Carbon Compounds (10)

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. 

Answer

  • Soaps are sodium or potassium salts of long chain carboxylic acids.
  • Detergents are ammonium or sulphonate salts.
  • Cleansing action of soap - One part of soap molecule is ionic / hydrophilic and dissolves in water. The other part is non-ionic / carbon chain / hydrophobic part which dissolves in oil.
  • Thus soap molecules arrange themselves in the form of a micelle / diagram of a micelle. 

On rinsing with water, soap is washed off, lifting the oily dirt particles with it.

Soap does not form lather in hard water because of the reaction of soap with Ca and Mg ions present in hard water which forms insoluble ppt. / scum.

Problems due to the use of detergents are:

  • Detergents are non-biodegradable.
  • It leads to water or soil pollution.
  • It can also cause skin problems.
Exam Year: 2015