Editing Chain reaction (section)

===Further chemical examples===
* The reaction 2 H<sub>2</sub> + O<sub>2</sub> → 2 H<sub>2</sub>O provides an example of chain branching. The propagation is a sequence of two steps whose net effect is to replace an H atom by another H atom plus two OH radicals. This leads to an explosion under certain conditions of temperature and pressure.<ref>Laidler K.J., ''Chemical Kinetics'' (3rd ed., Harper & Row 1987) p. 323-8 {{ISBN|0-06-043862-2}}</ref>
** H• + O<sub>2</sub> → •OH + •O•
** •O• + H<sub>2</sub> → •OH + H•
* In [[chain-growth polymerization]], the propagation step corresponds to the elongation of the growing [[polymer]] chain. Chain transfer corresponds to transfer of the activity from this growing chain, whose growth is terminated, to another molecule which may be a second growing polymer chain. For polymerization, the [[kinetic chain length]] defined above may differ from the [[degree of polymerization]] of the product macromolecule.
* [[Polymerase chain reaction]], a technique used in [[molecular biology]] to amplify (make many copies of) a piece of [[DNA]] by ''[[in vitro]]'' [[enzyme|enzymatic]] [[DNA replication|replication]] using a [[DNA polymerase]].