February 13, 2012
The Haber process, also called the Haber–Bosch process, is the nitrogen fixation reaction of nitrogen gas and hydrogen gas, over an enriched ironor ruthenium catalyst, which is used to industrially produce ammonia.
Despite the fact that 78.1% of the air we breathe is nitrogen, the gas is relatively unavailable because it is so unreactive:nitrogen molecules are held together by strong triple bonds. It was not until the early 20th century that the Haber process was developed to harness the atmospheric abundance of nitrogen to createammonia, which can then be oxidized to make the nitrates and nitrites essential for the production of nitrate fertilizer and explosives. Prior to the discovery of the Haber process, ammonia had beendifficult to produce on an industrial scale.
The mixture of nitrogen and hydrogen going into the reactor is in the ratio of 1 volume of nitrogen to 3 volumes of hydrogen.
Avogadro's Law says that equalvolumes of gases at the same temperature and pressure contain equal numbers of molecules. That means that the gases are going into the reactor in the ratio of 1 molecule of nitrogen to 3 of hydrogen.That is the proportion demanded by the equation.
In some reactions you might choose to use an excess of one of the reactants. You would do this if it is particularly important to use up as much aspossible of the other reactant - if, for example, it was much more expensive. That doesn't apply in this case.
There is always a down-side to using anything other than the equation proportions. If youhave an excess of one reactant there will be molecules passing through the reactor which can't possibly react because there isn't anything for them to react with. This wastes reactor space -particularly space on the surface of the catalyst.
The Haber process is important today because the fertilizer generated from ammonia is responsible for sustaining one-third of the Earth's population. It is...