# In condensation reactions, the atoms th make up a water from what?

Aug 31, 2016

The water derives from an hydroxyl group on one of the reactants, and (usually) a hydrogen from another reagent.

#### Explanation:

Now, typically, in a condensation reaction, we spit out water molecules, and typically we would add an acid, ${H}^{+}$.

Esterification, the coupling of an acid and a alcohol, is a typical condensation reaction:

$R O H + H O \left(O =\right) C R ' \rightarrow R O \left(O = C\right) C R ' + {H}_{2} O$

As water is a stable molecule, these reactions are thermodynamically downhill. Because we can remove the water molecule, as a volatile azeotrope with benzne or toluene, the reaction can be driven to completion.