Which liquids are miscible with liquid ammonia?



Structural formula
No structural formula available
General
Surname Ammonium hydroxide
other names

Ammonia solution, water, caustic, caustic ammonia, caustic ammonia, ammonia, stag's horn, caustic ammonia, ammonium hydrate

Molecular formula NH4OH
CAS number 1336-21-6
Brief description colorless pungent smelling liquid
properties
Molar mass 35.1 g mol−1
Physical state liquid
density 0.91 g cm−3 (25 %)
0.88 g cm−3 (32 %)
Melting point −57.5 ° C (25%)
−91.5 ° C (32%)
boiling point 37.7 ° C (25%)
24.7 ° C (32%)
Vapor pressure

483 hPa (25%)
837 hPa (32%) (20 ° C)

solubility

completely miscible with water

safety instructions
MAK

20 ml m−3; 14 mg m−3

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions.

Ammonium hydroxide, also Ammonia or Ammonia water, in the laboratory language only z. B. 25% ammonia called, is primarily a physical solution of ammonia (NH3) in water (H2O), in which there is partial protolysis from water to ammonia, and which is therefore basic. The name ammonium hydroxide suggests that it is an isolable substance, but that is not possible. Therefore, this term is actually not completely correct, but is still used because it characterizes the behavior of the substance. In the highest concentration, ammonia water has a density of 0.880 g / cm³ (= 32% ≙ 620 l NH3 in 1 l H2O).

The food additive label is E 527.

Emergence

When ammonia (NH3) in water (H2O) is dissolved, ammonia molecules (which are built into the polymeric hydrogen bridge system water and are therefore physically dissolved) intercept individual protons produced by the autoprotolysis of the water:

.

Most of the newly formed molecules react back again, so that most of the dissolved ammonia continues as NH3, and not as NH4+ is present.

properties

Ammonium hydroxide solutions basically contain a substantial proportion of ammonia, which, physically dissolved, i.e. mixed with the water, evaporates much faster due to the higher vapor pressure, which is why the ammonia concentration in open vessels decreases over time. The typical, pungent licorice-like smell of ammonia occurs. This can be demonstrated impressively by mixing this ammonia in the air with hydrogen chloride, such as that found in e.g. B. analogous from conc. Hydrochloric acid evaporates, brings into contact, forming a thick white smoke of ammonium chloride in a non-aqueous acid-base reaction.

An addition compound (NH3 · H2O), which melts at −77 ° C. However, this is not the actual ammonium hydroxide, but rather ammonia crystals with attached water.

safety instructions

The labeling data in the table refer to the concentrated solution (= 32%). The EU has defined the following classifications for other concentration ranges:

C ≥ 25% C, N R: 34-50
10% ≤ C < 25=""> C. R: 34
5% ≤ C < 10=""> Xi R: 36/37/38

history

Salmiak is said to have already been known to the ancient Egyptians and was first postulated by Arrhenius due to his success in describing bases.

use

Salmiak spirit is used as a household remedy for cleaning surfaces in the household, but is also an insider tip for repelling wasps. For this purpose, a little ammonia is placed in a small bowl in closed rooms; wasps will avoid the room from now on because of the smell. Outside a building, you take paper towels that are soaked in ammonia and distribute them near the wasp's nest.

It is also recommended to use it for cleaning and combating the fungus in the case of light to moderate mold growth on walls.

Another area of ​​application is the control of pests such as silverfish.

hazards

Ammonium hydroxide solutions with an ammonia content of 10% or more are corrosive. Long-term inhalation can lead to impotence, e.g. B. in tobacco smoke from cigarettes.

Ingestion of ammonia water causes severe pain, gastric catarrh, bloody vomiting, lung and voice damage, which are often fatal. It also attacks the eyes.

Since ammonia is the primary evaporation product, the dangers of this substance also apply to the vapors of ammonia.

Categories: Corrosive Substance | Environmentally hazardous substance | Chemical solution