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All other proposed formation reactions have rate constants of between two and 13 orders of magnitude smaller, making their contribution to the abundance of ammonia relatively insignificant. [181] As an example of the minor contribution other formation reactions play, the reaction: H 2 + NH 2 → NH 3 + H. has a rate constant of 2.2 × 10 −15.
Fritz Haber, 1918. The Haber process, [1] also called the Haber–Bosch process, is the main industrial procedure for the production of ammonia. [2] [3] It converts atmospheric nitrogen (N 2) to ammonia (NH 3) by a reaction with hydrogen (H 2) using finely divided iron metal as a catalyst:
In aqueous solution, ammonia deprotonates a small fraction of the water to give ammonium and hydroxide according to the following equilibrium: . NH 3 + H 2 O ⇌ NH + 4 + OH −.. In a 1 M ammonia solution, about 0.42% of the ammonia is converted to ammonium, equivalent to pH = 11.63 because [NH +
As a result, high pressures are needed to drive the reaction forward. The German chemists Fritz Haber and Carl Bosch developed the process in the first decade of the 20th century, and its improved efficiency over existing methods such as the Birkeland-Eyde and Frank-Caro processes was a major advancement in the industrial production of ammonia.
For many substances, the formation reaction may be considered as the sum of a number of simpler reactions, either real or fictitious. The enthalpy of reaction can then be analyzed by applying Hess' law, which states that the sum of the enthalpy changes for a number of individual reaction steps equals the enthalpy change of the overall reaction.
A number of side reactions compete with the formation of nitric oxide. Some reactions convert the ammonia to N 2, such as: 4NH 3 + 6NO → 5N 2 + 6H 2 O. This is a secondary reaction that is minimised by reducing the time the gas mixtures are in contact with the catalyst. [6] Another side reaction produces nitrous oxide:
Ammonium carbamate can be formed by the reaction of ammonia NH 3 with carbon dioxide CO 2, and will slowly decompose to those gases at ordinary temperatures and pressures. It is an intermediate in the industrial synthesis of urea (NH 2 ) 2 CO , an important fertilizer .
Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged molecular ion with the chemical formula NH + 4 or [NH 4] +.It is formed by the addition of a proton (a hydrogen nucleus) to ammonia (NH 3).