Editing Hydrogen (section)

=== Hydrogenation ===
[[Hydrogenation]], the addition of {{chem2|H2}} to various substrates, is done on a large scale. Hydrogenation of {{chem2|N2}} produces ammonia by the [[Haber process]]:<ref name="UllmannHuse" />
:{{chem2|N2 + 3 H2 → 2 NH3}}
This process consumes a few percent of the energy budget in the entire industry and is the biggest consumer of hydrogen. The resulting ammonia is used in fertilizers critical to the supply of protein consumed by humans.<ref name="Smil_2004_Enriching">{{cite book |last1=Smil |first1=Vaclav |title=Enriching the Earth: Fritz Haber, Carl Bosch, and the Transformation of World Food Production |date=2004 |publisher=MIT |location=Cambridge, MA |isbn=978-0-262-69313-4 |edition=1st}}</ref> Hydrogenation is also used to convert [[unsaturated fat]]s and [[vegetable oil|oils]] to saturated fats and oils. The major application is the production of [[margarine]]. [[Methanol]] is produced by hydrogenation of carbon dioxide; the mixture of hydrogen and carbon dioxide used for this process is known as [[syngas]]. It is similarly the source of hydrogen in the manufacture of [[hydrochloric acid]]. {{chem2|H2}} is also used as a [[reducing agent]] for the conversion of some [[ore]]s to the metals.<ref>{{cite web|author=Chemistry Operations|date=15 December 2003|url=http://periodic.lanl.gov/1.shtml|title=Hydrogen|publisher=Los Alamos National Laboratory|access-date=5 February 2008|archive-url=https://web.archive.org/web/20110304203439/http://periodic.lanl.gov/1.shtml|archive-date=4 March 2011}}</ref><ref name="housecroft" />