What is ammonium hydroxide?

Ammonium hydroxide

The ammonium hydroxide , better known as liquid ammonia, is a mixture of water and ammonia gas having multiple uses. It has no color and its smell is very strong . It is found in its natural state in the environment, as well as in the human body, where it performs functions such as synthesizing proteins. Industrially it is produced for various purposes. For agriculture, home cleaning and medicine, among others. This chemical compound should be used with caution, since inadequate exposure is harmful to health.

Ammonium hydroxide 

What is ammonium hydroxide?

Ammonium hydroxide is a chemical compound that is generated by diluting ammonia gas with water . It is also called as liquid ammonia or ammonia. It is found in the natural environment in plants, animals, and humans. It is also created industrially for various uses.

  • features
  • Formula and nomenclature
  • Structure
  • Physical properties
  • Chemical properties
  • Ammonium Hydroxide Reactivity
  • Ammonium hydroxide on other planets
  • How it is produced in industries
  • Natural ammonium hydroxide
  • Functions of ammonia
  • Uses of ammonium hydroxide
  • Risks


  • It comes in a liquid state
  • Colorless
  • Can’t isolate
  • Sharp and strong odor
  • It is corrosive (dissolves copper and zinc)
  • It has a density of 0.90 g / cm3 at 25 ºC.
  • It has a pungent , unpleasant taste .

Formula and nomenclature

The molecular formula of Ammonium Hydroxide is NH4OH or H5NO


Its structure is made up of an “aqueous ammonia gas solution”. In the liquid its structure is not defined except by a circumstantial ability of ions “NH4 + and OH- solvated by water molecules”. Its PH is: 11.6 (1 N solution); 11.1 (0.1 N solution) and 10.6 (0.01 N solution).

Physical properties

  • It reaches a boiling point at 38 ºC (25%).
  • The solubility is only possible in aqueous solution.
  • The solubility in water is miscible in unlimited proportions.
  • Its density ranges from 0.90 g / cm3 at 25 ºC.

Chemical properties

  • The dissociation constant for ammonium hydroxide is: pKb = 4.767; Kb = 1.71 x 10-5 at 20 ° C; and pKb = 4.751; Kb = 1,774 x 10-5 at 25 º C.
  • A rise in temperature almost imperceptibly raises the basicity of ammonium hydroxide.
  • Its concentration is up to approximately 30%, for NH4 + and OH– ions.
  • When it is at temperatures that are well below 0ºC, and when there is also immense pressure around it, like those found in the nuclei of frozen moons in space, water and ammonia freeze

Ammonium Hydroxide Reactivity

  • May react violently with strong acids such as sulfuric acid, hydrochloric acid, and nitric acid. It is also aggressive when combined with halogens and dimethyl sulfate.
  • Reacts with various metals such as lead, silver, zinc, and copper. Likewise, it does so with the salts of these metals by generating explosive mixtures and the release of hydrogen gas (flammable).
  • Due to its corrosive effect, it is not used with aluminum and copper, or with galvanized metals.
  • It reacts producing gaseous ammonia when it combines with bases such as potassium or sodium hydroxides that are very strong.

Ammonium hydroxide on other planets

Scientists have verified that the clouds of the planet Jupiter are composed of ammonium hydroxide in dilute solutions. Despite this, space probes have failed in their search for water in these cloud formations. There is frustration in this regard, because after learning that there is evidence of the presence of anhydrous NH4OH crystals, it was expected to find water.

How it is produced in industries

Industries that generate ammonia obtain it through a method called Haber-Bosch. This consists of reacting hydrogen and nitrogen gases, after using potassium oxide, ferric ion and aluminum oxide as catalysts. It is subjected to high temperatures and pressure, to have a yield of 10 to 20 percent . After the reaction, ammonia is obtained which, in turn, after undergoing an oxidation process, produces nitrates and nitrites. With these last two, ammonium nitrate and nitric acid are obtained, widely used in fertilization.

Natural ammonium hydroxide

Ammonium hydroxide and ammonia are naturally and commonly found in soils, water, and air on planet Earth . Likewise, it is present in flora and fauna, as well as in human beings. Nitrogen is essential for the subsistence of animals and plants and this element is generated from ammonia. Ammonia is also produced in the human body . This originates in the tissues and organs, as well as some bacteria that are found in the intestine and that are beneficial for health.

Functions of ammonia

One of the important tasks of ammonia in living beings is to synthesize proteins . These are made up of a score of different amino acids. Plants synthesize them, for the most part, with the help of atmospheric nitrogen, but animals do not. The human body can synthesize some and others simply pass intact after being consumed. However, the amino acids it synthesizes do so thanks to the presence of microorganisms in the gastrointestinal tract thanks to the action of ammonia ions. In addition, ammonia ensures that the body pH is balanced.

Safety in your employment to process food

The Food and Drug Administration (Food and Drug Administration) states in its regulations that ammonium hydroxide (and other preparations containing ammonia) is recognized as “safe” or “GRAS” when it is used as a pH control agent, leavening and for surface finishing when processing food in industries. The only limitation is that the process is carried out with the current manufacturing steps.

Uses of ammonium hydroxide

In food

  • It is used as an additive in various processed foods to act as a leavening agent, to control pH, and for surface finishes on foods.
  • It is used as an antimicrobial in meat foods , since it eliminates bacteria, including E. coli. Ammonium hydroxide hinders the growth of bacteria in cattle, after its pH-regulating effect in the animal’s intestine, which is where E. coli appears.
  • The variety of foods in which ammonium hydroxide is used is wide. Among them are those that are baked, candies, puddings, cheeses and chocolates.

Medical uses

  • It is used externally on the skin to treat insect or animal stings and bites.
  • It serves as an antacid, antiflatulent (expulsion of gases) and other disorders of the digestive system.
  • Its topical use acts as a rubefacient in acute and chronic muscle and bone pain.

Use in agriculture

  • It is not used directly in plants, but it does have a function as a fertilizer for crops.
  • The atmospheric nitrogen produces the ammonia, then it is taken refrigerated to the places where it will be used.
  • The soil is injected with pressurized ammonia . There it reacts with edaphic water and becomes ammonium (NH4 +). Ammonium hydroxide is also generated. Both compounds originate nitrogen, this together with potassium and phosphorus nourish plants and are essential for them to grow properly.

Industrial uses and more

  • Paint additive
  • Plasticizing agent
  • It is added to dyes to color hair
  • To treat wastewater (antimicrobial)
  • Pool water purifier
  • As a cleaner for commercial and industrial products
  • Production of soaps, detergents and inks.


  • Causes eye irritation and / or damage on direct contact
  • In high concentrations it can irritate and burn the skin
  • If inhaled it will cause irritation of the respiratory tract, coughing, shortness of breath or suffocation. Continuous exposure can infect the bronchial tubes or irritate the lungs.
  • Being in contact with a high degree of concentration of ammonium hydroxide can cause pulmonary edema.
  • Other symptoms of high and toxic exposure may include fainting, low blood pressure, loss of vision, wheezing, sore throat, vomiting, and bloody stools.
  • Ammonium hydroxide is not flammable, but if a fire occurs it will create ammonia gases that can explode and aggravate the event.
  • Unfortunately, ammonium hydroxide is used in the production (against the law) of methamphetamines, substances highly harmful to health.

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