Potassium Carbonate - K₂CO₃

Bookmark added to your notes.
View Notes

What is Potassium Carbonate?

Potassium Carbonate is an inorganic compound having the chemical formula K2CO3 and the chemical name Potassium carbonate. It is otherwise called Carbonate of potash, or Pearl ash, or Di-potassium carbonate. It is defined as a dipotassium salt of carbonic acid and can be widely used in the production of soap and glass.

Pearl ash is a hygroscopic and deliquescent white powder. It is odourless and tastes the same as alkaline. It is readily soluble in water but insoluble in acetone, alcohol, and ethanol. It contains a pH of 11.6. It is a primary component of potash.

Properties of Potassium Carbonate – K₂CO₃

Let us look at the important properties of Potassium Carbonate as listed below:

Potassium Carbonate Properties


Potassium Carbonate

Chemical Formula


The density of Potassium carbonate

2.43 g/cm3

Molecular weight/molar mass of K2CO3

138.205 g/mol

Melting Point of Potassium carbonate

891 °C

Boiling Point of Potassium carbonate


Potassium Carbonate Structure – K₂CO₃

The Potassium Carbonate Structure can be illustrated as follows:

(Image to be added soon)


Historically, the Di-potassium carbonate compound was created by baking potash in a kiln. The white powder, which was produced, was the potassium carbonate. In 1790, Samuel Hopkins was awarded the first patent, issued by the US Patent Office for an improved process of making potash and pearl ash.

Production of Potassium Carbonate

  • Potassium Carbonate can be prepared commercially by reacting the potassium hydroxide (KOH) compound with carbon dioxide (CO2). The chemical reaction for the same can be given as follows:

2 KOH + CO2 → K2CO3 + H2O

  • An alternative process to obtain potassium carbonate is by treating it with carbon dioxide (CO2) in an organic amine presence, which results in the potassium bicarbonate, and on further calcination of KHCO3 produces potassium carbonate. The chemical reaction for the same can be given as follows:

2 KHCO3 → K2CO3 + H2O + CO2

Uses of Potassium Carbonate

Let us look at the use of potassium carbonate as listed below:

  • In the basic inorganic chemical industry, light industry and medicine industry, Potassium carbonate is treated as an important raw material. It has been primarily used in the production of electrode tube, optical glass, TV tube, printing items, bulb, dye, photography items, ink, sodium metasilicate, plating, polyester powder, leather, crystal, potash soap, drugs, and ceramic building materials.

  • On the other side, it can also be used as a dry powder, rubber protective agent, and gas adsorbent.

  • This compound can be used for carbon dioxide removal in chemical fertilizer syngas.

  • This is also used as a potassic fertilizer.

  • Potassium carbonate also extends its application in various fields such as gourmet, food, and detergent builder.

Potential Health Effects

  • Skin Contact: Exposure of potassium carbonate to the skin can cause irritation and redness. This material is not given as a skin sensitizer according to the studies with guinea pigs.

  • Eye Contact: Eye exposure can cause redness and severe irritation to the eyelids, conjunctiva. Prolonged and untreated eye contact may cause severe and permanent eye damage.

  • Ingestion: Ingestion of this compound can cause oesophagal, oral, glottis redness, ulceration, irritation, stomach & intestinal irritation, edema, and burns. Ingesting in excess quantities can also cause vomiting, ulceration, shock, and even death.

  • Inhalation: Inhalation of this material may cause upper airway irritation, cough, redness of mouth, including upper airways.

Applications Potassium Carbonate

Let us look at the important applications of potassium carbonate:

  • As a mild drying agent where the other drying agents, like magnesium sulfate and calcium chloride. It may be incompatible and is not suitable for the acidic compounds. However, it can be useful in drying an organic phase if one contains a small amount of acidic impurity. It can also be used to dry some of the alcohols, ketones, and amines before distillation.

  • In cuisine, where it has several traditional uses, it is also an ingredient in grass jelly production, which is food consumed in Southeast Asian and Chinese cuisines, and Chinese hand-pulled noodles and moon cake as well. Also, it is used to tenderize tripe. Often, German gingerbread recipes use potassium carbonate as a baking agent, although with a hartshorn combination. Potassium carbonate usage must be limited to a specific amount to prevent harm and advised not to be used without guidance.

  • In the cocoa powder, the alkalization can produce Dutch process chocolate by balancing the pH (it means, reduce the acidity) of natural cocoa beans; it enhances aroma. The adding of the potassium carbonate process to cocoa powder is generally called "Dutching" (and the products are called Dutch-processed cocoa powder). The process was first developed in 1828 by Dutchman Coenraad Johannes van Houten.

Potassium Carbonate's Food Safety

While not every potassium carbonate is safe to add with food, commercially, food-grade potassium carbonate is available. It is safe to add the same potassium carbonate to food. Of course, potassium carbonate is reasonably a strong base, so it does not taste very good if we had more than just a small amount.

FAQ (Frequently Asked Questions)

1. How can potassium carbonate be prepared?

Commercially, potassium carbonate is prepared using a reaction involving potassium hydroxide and carbon dioxide. In the alternative process, potassium chloride is treated with carbon dioxide in the presence of an organic amine to produce potassium bicarbonate, which is then calcined to give potassium carbonate.

2. What are the uses of potassium carbonate?

Potassium carbonate can be widely used for soap and glass production. It can also be used as a drying agent, which is mild in nature. Several wine production processes involve this compound used as a buffering agent. This compound is also used as a fire suppressant.

3. Comment on potassium carbonate solubility in water.

Potassium carbonate compound is highly soluble in water. However, when this compound dissolves in water, it dissociates into carbonate and potassium ions. At 20 degrees Celsius of temperature, the solubility of potassium carbonate in water corresponds to 1120 grams per litre.

4. Explain if potassium carbonate is reactive?

Reasonably, we can say yes. It's deliquescent, forming a basic solution in water, and its reaction with acids produces an aqueous solution of the water, salt, and carbon dioxide gas. The chemical reaction is given below:

K2CO3 + 2HCl →2KCL +H2O + CO2

The basic properties of this compound have seen its usage as a buffering agent, water softener, and an acidity regulator in certain food products.