The smell of this gas is known to everyone - it immediatelyYou can feel it if you open the jar with ammonia. Something about his properties we were told at school. It is also known that it is one of the key products of the chemical industry: it is the easiest way to turn it into nitrogen, which so does not like to enter into chemical reactions. Ammonia is the first point from which the production of many nitrogen-containing compounds begins: various nitrites and nitrates, explosives and aniline dyes, drugs and polymeric materials ...

Brief information

ammonia molecule
The name of this substance comes fromGreek "hals ammoniakos", which in translation means ammonia. The ammonia molecule is a kind of pyramid with a nitrogen atom at its apex, and three hydrogen atoms at its base. The formula for this compound is NH3. Under normal conditions, ammonia is a colorless gas with an asphyxiating, pungent smell. Its density at -33.35 ° C (boiling point) is 0.681 g / cm3. And this substance melts at -77.7 ° С. The molar mass of ammonia is 17 grams per mole. The pressure of 0.9 MPa causes the ammonia to contract at room temperature. It is produced in the industry under pressure by catalytic synthesis from hydrogen and oxygen. Liquid ammonia is a highly concentrated fertilizer, a refrigerant. Care should be taken with this substance, as it is toxic and explosive.

Curious facts

Liquid ammonia has rather unusual properties. Outwardly it resembles plain water. Like H2Oh, it perfectly dissolves many organic andinorganic compounds. Most salts in it dissociate when dissolved in ions. At the same time, chemical reactions, in contrast to water, occur in it quite differently.

ZnCl2

BaCl2

KCl

NaCl

KI

Ba (NO3) 2

AgI

Solubility at 20 ° C, based on 100 g of solvent

ammonia

0

0

0.04

3

182

97

207

water

367

36

34

36

144

9

0

The data in this table lead to the idea that liquid ammonia is a unique medium for carrying out certain exchange reactions that are practically unworkable in aqueous solutions.

ammonia mass
For example:

2AgCl + Ba (NO3)2 = 2AgNO3 + BaCl2.

Since NH3 is a strong proton acceptor, aceticacid, in spite of the fact that it is considered to be weak, will dissociate completely, just as strong acids do. Of greatest interest are solutions in ammonia alcohol of alkali metals. Back in 1864, chemists noticed that if they were given some time, ammonia would evaporate, and in the sediment would be pure metal. Almost the same thing happens with aqueous solutions of salts. The difference is that the alkali metals, although in a small amount, but still react with ammonia, resulting in the formation of salt amides:

2Na + 2NH3 = 2NaNH2 + H2.

The latter are quite stable substances, but when they come into contact with water they immediately disintegrate:

NaNH2 + H2O = NH3 + NaOH.

ammonia is
When investigating the properties of liquid ammonia, chemistsWe noticed that when the metal is dissolved in it, the volume of the solution becomes larger. Moreover, its density decreases with this. This is another difference between the solvent in question and ordinary water. It's hard to believe, but the concentrated and diluted solution of any alkali metal in liquid ammonia does not mix, despite the fact that the metal in both of them is the same! Thanks to the experiments, new and surprising facts are constantly being discovered. Thus, it turned out that a solution of sodium, frozen in liquid ammonia, has very little resistance, and therefore NH3 can be used to produce a superconducting system. It is not surprising that this gas and its solutions are still of interest to the minds of both physicists and chemists.

</ p>