Why are detergents better than soaps in cleaning?

[Fatima Saleem]

In terms of the chemistry of a cleaning agent, both soaps and detergents contain a hydrophilic (polar) and hydrophobic (non-polar) component. These two part of the organic chain will interact to form a force of attraction between water and other organic substances (such as oils and grease) respectively.

In terms of their strength, a soap contains a COO- group, that has formed in the presence of a Sodium or Potassium ion. This will be capable of dispersing the attractive forces between water molecules, known as "Surface Tension", but will not be able to do this indefinitely. Detergents on the other hand contain an O-SO3- group with the same ions which can hold this force at bay.

In terms of useage; soaps will undergo substitution reactions with minerals such as Calcium or Magnesium in "Hard Water". These derivatives are insolunle, and will form "scum" on the surface of the water, detracting from the effectiveness of the soap. Detergents on the other hand are less likely to form these alternate salts, but when they do these salts that form are soluble.