Formation Reaction Definition

One mole of product is made in a formation reaction.
One mole of product is made in a formation reaction. iStock Vectors, Getty Images

A formation reaction is a reaction where the one mole of product is formed.

Formation Reaction Example

Hydrogen and oxygen combine to form water by the formula:
2 H2 + O2 → 2 H2O
The formation reaction of this process is:
H2 + ½ O2 → H2O