Re: What is the difference between soap and detergent? (chemically speaking)

There is a difference between these two terms.
A soap is a natural fatty substance (called fatty acids)
which has been reacted with lye (sodium hydroxide).
A detergent is any type of cleaner which does
not contain a soap as its main ingredient.  Detergents
typically contain synthetic surfactants which
perform in many ways better than soap.  If you want to
know more about detergents, try 
http://www.chemistry.co.nz/surfactants.htm

I hope this helps,

Greg Webb