Ammonium salts - methods of production, use in the national economy

In chemical compounds, NH4 + manifests itself as a positive singly charged cation of alkali metal. When interacting with acid anions, substances with a crystalline structure are formed : ammonium salts: NH4N03 nitrate , NH4C1 chloride, sulfate (NH4) 2S04, which consist of an acid anion and an ammonium group.

Ammonium salts are obtained in the course of the neutralization reaction, which occurs during the reaction of ammonia with acids.

Ammonium salts, as in principle the majority of alkali metals, can dissociate (split into cations and anions) in aqueous solutions into ions: ammonium salts, like alkali metal salts, dissociate into ions:

NH4N03 ↔ NH4 ++ NO3-

During the heating process, the dry ammonium salts decompose into ammonia and acid; This process is also called thermal dissociation.

The resulting acid (for example, hydrochloric acid), together with NH3, evaporates and, when cooled, combines with ammonia to give the salt. It should be said that the process of reversible decomposition is also possible:

NH3 + HCl ↔ NH4Cl

Thus, while heating, the ammonia is sublimated, however, after a while, a white coating of ammonium chloride appears again on the upper parts of the tube. As a result of the formation of the salt by a nonvolatile acid, for example (NH4) 2S04, only NH3 escapes during heating, and the acid remains. Such a process is called an irreversible decomposition.

All ammonium salts are readily decomposed by alkalis (with heating) with the evolution of ammonia:

NH4 + + OH -NH3 ↑ + H20

This reaction is used to recognize mineral fertilizers with an ammonium form of nitrogen.

The interaction of ammonium carbonate with mineral and organic acids liberates carbon dioxide. In the interaction of sulfate or ammonium chloride with AgNO3 or BaCl, characteristic precipitates, white, form.

Ammonium salts: examples

Ammonium salts Widely used in agriculture. It is an excellent material for mineral fertilizing of plants (for example, ammonium sulfate - (NH4) 2S04). As is known, plants can only metabolize nitrogen in a bound form (NO3, NH4). Therefore, nitrogenous compounds are very effective. Of great importance is ammonium nitrate, which contains ammonium NH4 nitrate NO3-nitrogen.

Dihydrogenphosphate and ammonium hydrogen phosphate, known under the names of NH4H2P04 ammophos and diammophos (NH4) 2HP04, contain two chemical plant nutrients, nitrogen and phosphorus. Ammonium salts are a part of fertilizer mixtures.

In the reaction of ammonia with carbon monoxide (IV), urea or carbamide NH2-CO-NH2 is synthesized.

Ammonium chloride (NH4C1) or ammonia is used in galvanic cells, for dyeing and printing, tinning and soldering. In contact with the heated metal, ammonia decomposes into hydrogen chloride and ammonia. Hydrochloric acid interacts with an oxide that pollutes the surface of the metal, with the formation of a volatile salt.

It should be noted that solder adheres very well to the cleaned surface. NH4NO3 (ammonium nitrate) together with coal and aluminum salts are an integral part of the explosive - ammonal. These compounds are used in the development of rocks. Ammonium bicarbonate (NH4HCO3) is often used in the food and confectionery industries. This compound is also used as a preservative for various types of feed. NH4HCO3 has denitrofitsiruyuschimi properties, which helps to accelerate the maturation of the crop.

A qualitative reaction to ammonium salts. When the solution of ammonium salts with alkali is heated, ammonium hydroxide is formed, which is cleaved with the evolution of ammonia.

The presence of ammonia can be judged by the specific odor, as well as using colored paper indicators. To carry out this reaction, it is necessary to take 1.0 cm3 of ammonium salt solution, add 0.5 cm3 of sodium hydroxide solution and heat. In the process of heating ammonia is released, a characteristic odor is formed, red litmus turns blue.