What is potassium hydroxide?

Potassium hydroxide

The potassium hydroxide or KOH is made from potassium chloride electrochemically. It is a solid at room temperature. We also commonly find it as an aqueous solution. It is strongly alkaline and corrosive, therefore very dangerous for health. It is widely used in the manufacture of commonly used products.

What is potassium hydroxide?

The potassium hydroxide also known as caustic potash in the world of chemistry, is a mineral chemical combination . It is a hydroxide made up of a potassium atom, an oxygen atom and a hydrogen atom. It has numerous uses both in the industrial and commercial areas. Most revolve around their reaction with acids and their natural corrosion.

  • Potassium hydroxide characteristics
  • Structure
  • Formula
  • Nomenclature
  • Potassium hydroxide physical properties
  • Chemical properties
  • Obtaining
  • Potassium hydroxide uses
  • Usefulness of potassium hydroxide in the manufacture of fertilizers
  • Risks
  • First aid
  • Signs and symptoms

Potassium hydroxide characteristics

Among the most prominent characteristics of potassium hydroxide are the following:

  • It is a solid of white tonality in the form of granules.
  • It has a great ability to absorb the humidity of the environment.
  • It is fusible.
  • Without smell.
  • Obtains variable amounts of water.
  • Its dissolution in water is highly exothermic.

Typically the alkali metals, the alkaline earth and the hydroxides are caustic. This word comes from the Greek that refers to burning. In chemical sciences, a product is considered caustic when it burns organic tissues. These can be both acids and bases, organic or inorganic.


Potassium hydroxide has water in variable amounts, in addition to carbonates. At normal temperatures, the KOH crystal is monoclinic with each potassium atom. It is surrounded by a deformed octahedron of oxygen atoms.

At the same time the hydroxyl assemblies make up a zigzag chain attached by hydrogen, here the 0-0 distances are 3.35 A. Any significant hydrogen bond is discarded. Potassium hydroxide can be neutralized with certain acids such as hydrochloric.


Every chemical compound is made up of a total of two or more elements that make up its structure. To determine and know the components that originate it, a formula is used in chemistry.

In this case, the formula of this hydroxide is represented by the acronym of its elements: KOH.


The nomenclature of potassium hydroxide is given by 3 acronyms: KOH. They correspond to the English names of Potassium, Oxygen and Hydrogen, elements that make it up.

Potassium hydroxide physical properties

Pure potassium hydroxide is a solid at room temperature, but it is continuously obtained as an aqueous substance, in liquid form. The appearance as a substance and some physical properties are:

  • The substance is a strong base.
  • It is a solid element (90%).
  • Aqueous solution (50%).
  • Colorless white color.
  • Solubility : 120 g / l water 20 ° C.
  • Density 2.044 g / cm3 (20 ° C).
  • Melting temperature 406 ° C.
  • Boiling temperature 1327 ° C.
  • Molecular weight 56.1 g / mol.

Chemical properties

  • It is a strongly alkaline chemical compound
  • Reacts violently with acids.
  • It is corrosive in a humid environment with brass such as zinc, aluminum and lead.
  • It is soluble in water.


In nature we find potassium in large quantities. However, its great reactivity is not found in its pure state. Its minerals are found abundantly in evaporitic mud deposits or in natural salt mines. The sedimentary deposits were constituted by evaporations of the sea water .

Through various natural processes, the carbonate sequence, calcium sulfates and sodium salt were gradually created. When the right conditions were present, the precipitation of the so-called potassium salts began, such as sylvite, potassium chloride, and carnalite, humid potassium and magnesium chloride.

Specifically, potassium hydroxide originates from the electrolysis of potassium chloride in electrolytic cells. When the potassium chloride brine is housed in the electrolytic cabinet, it results in a solution of potassium hydroxide and products of the chlorine and hydrogen group.

The final consequence is a totally pure KOH solution with a weight percentage of 45-50grs . Because it is hygroscopic, it absorbs water from the atmosphere , which causes it to dissolve in the open air.

Potassium hydroxide uses

It is very useful at an industrial and commercial level. The uses are multiple and of great relevance in human activity. It is based on a variety of solid and liquid products.

It is widely used in the production of soaps, among which are those made from vegetable oil, coconut oil and fatty acid. It is present in substances for tanning leather, removing cuticle, cleaning drain pipes and in many other chemical compounds.

In industry it has a multiplicity of applications such as the production of potassium phosphates and potassium carbonate. The latter has numerous and different uses such as:

  • The use of rare crystals as television tubes.
  • In additives for the preparation of edibles mainly because it has the property of regulating acidity. Some foods are chocolate, pasta, margarines, jams.
  • In pigments and dyes.
  • Separating carbon dioxide from industrial gas streams.
  • In boiler compounds.
  • Titanium enamels.
  • As a chemical it includes potassium acetate, silicate, bisulfite, fluoride, ferrocyanide and others.
  • In electroplating baths
  • Vat coloring and textile printing

Usefulness of potassium hydroxide in the manufacture of fertilizers

Due to its current notableness, its use in the manufacture of agricultural fertilizers stands out. It constitutes approximately 93% of consumption globally. Along with nitrogen and phosphorus , potassium hydroxide forms the so-called macronutrients. They supply most of the shortages on agricultural land.

Undoubtedly, it is essential for the development of crops, playing a significant role in providing the energy necessary for the development of plants.

It has very beneficial effects on the improvement and quality of the harvested products. If, on the contrary, there is an absence of potassium, growth is delayed. Example, are fruits and vegetables that show a poor appearance in relation to size and shape.

On the other hand, it collaborates in resistance and tolerance to the attacks of infections, insects and snowfalls and participates in photosynthesis and protein synthesis.


The risks posed by this chemical element are considerable, both by ingestion and by inhalation since it is very toxic and flammable. Considerable care must be taken when handling it, because potash is a truly aggressive compound. It is very absorbent and can easily end up floating in the environment.

In this sense, it is extremely necessary to take into account all the precautions and essential safety regulations when working with this compound.

  • Strictly follow the advice and precautions presented on the labels.
  • Make sure to store it in a place free from humidity and that it is fully sealed.
  • Always keep away from children without the possibility of being reached.
  • Use the appropriate equipment such as gloves, mask, safety boots. Rubbing with the skin causes serious injuries and contact with the eyes is highly corrosive.
  • Do not smoke, eat or drink during handling.
  • If possible, take a bath or apply adequate personal hygiene rules after handling.
  • Store in hermetically closed tanks and place in dry environments.

First aid

In case of ingestion, you should wash your mouth immediately. If the person is conscious, give as much water or milk to drink as possible. If he is unconscious, do not induce vomiting and keep him in a lateral position. If required, he must be transferred to a health center.

Signs and symptoms

Symptoms due to ingestion of potassium hydroxide include:

  • Strong abdominal discomfort.
  • Respiratory problems thanks to the impediment of the entry of air due to swelling of the pharynx , burns in the mouth and throat.
  • Fainting.
  • Strong pain in the mouth and throat.
  • Diarrhea.
  • Hypotension
  • Burning, decreased vision and severe pain in the eyes when they are affected.

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