Synthetic detergents, which are also known as
syndets, were developed to overcome the difficulties
faced while using soap as a cleaning agent. Soaps
when used in hard water precipitate the calcium
and magnesium salts, due to which it's effectiveness
as a cleaning agent deteriorates.
In addition, edible oil & fats, which could
be put to other uses, are used as raw materials
for the manufacture of soaps. These problems are
circumvented in synthetic detergents that are
highly stable in hard water and do not consume
valuable and expensive oil for their manufacture.