# What is a soap, and how are they made?

A soap is a (alkali metal) salt of a fatty acid, a long chain carboxylic acid. A typical soap is $\text{sodium stearate}$, ${H}_{3} C {\left(C {H}_{2}\right)}_{16} C {O}_{2}^{-} N {a}^{+}$. Depending on the metal salt, and the length and source of the soap chain, different soaps (and later detergents) can be manufactured. Soaps made from olive oils are particularly fine, and mild.