Condensation Reaction
A reaction in which two molecules join with the elimination of a small molecule, usually water.
Formula / equation
A–OH + H–B → A–B + H₂O
Unit
Dimensionless
In depth
Condensation builds larger molecules while expelling a by-product, so unlike addition it is not fully atom-economical. Repeated many times, it produces condensation polymers such as polyesters and polyamides, and it is how nature assembles peptides, polysaccharides and nucleic acids.
Examples in the real world
Ethanoic acid with ethanol forming ethyl ethanoate and water; two amino acids forming a peptide bond.