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Potassium Acetate

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Potassium Acetate Structure

Potassium acetate is also known as the potassium salt of acetic acid. The potassium acetate formula is \[ CH_{3}CO_{2}K \]. The reaction of acetic acid with a potassium base, which can either be potassium carbonate or potassium hydroxide, results in the formation of potassium acetate. Potassium acetate is also known as Potassium ethanoate, diuretic salt, acetic acid, or potassium salt. 


It plays an important macromineral role in various physiological functions and maintaining normal renal function and blood pressure. It is also required for nerve conduction, cardiac and skeletal muscle contraction, and nucleic acid synthesis. 


Potassium Acetate is formed by one acetate anion \[CH_{3}COO^{-}\] and one potassium cation \[K^{+}\]. Both the ions are bonded by ionic bonds. However, the elements of anion acetate are bonded by covalent bonds, and both the oxygen have a resonance stabilisation between them. Its structure is given below:


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Potassium Acetate Properties

In a potassium salt, an equal number of acetate and potassium ions are present. Potassium acetate does not occur naturally. The salt was used earlier as expectorants and diuretics. 


Chemical Properties of Potassium Acetate

  1. Potassium Acetate is a deliquescent white crystalline solid which is insoluble in organic solvents like ether, but soluble in both alcohol, ammonia, and water.

  2. Pure Potassium Acetate has a faint acetic smell, or we can say it is odourless, which has a saline taste.

  3. It is used as a dehydrating and analytical agent in the manufacturing of crystal glasses and medicines.

  4. Potassium acetate is a canonicalised compound. There are five heavy atoms in potassium acetate and 0 formal charges. 

  5. It lowers the blood pressure by flushing out the salt from the body as potassium present in the salt helps in maintaining the blood pressure. It also helps in maintaining intracellular toxicity which is needed for smooth muscle contraction, and normal renal function.


Physical Properties of Potassium Acetate

  1. The compound is a dry powder, colourless, odourless, and exists in the form of deliquescent crystals or white crystalline powder. Potassium acetate has a faint acetic smell. 

  2. The solubility of potassium acetate in water is 100g/ml at 20 degrees celsius. 

  3. The Potassium Acetate formula is \[CH_{3}CO_{2}K\] and has a molar mass of 98.142g/mol.

  4. Potassium Acetate density is 1.8 grams per cubic centimetre.

  5. The potassium Acetate melting point is 292°C.

  6. Potassium Acetate has a higher boiling point and decomposes at a higher temperature.

  7. The pH value of diuretic salt lies between 7.5 - 9.0.

  8. The number of hydrogen bond donors is 0, the number of hydrogen bond acceptors is 2, and the number of rotatable bonds is 0. The topological polar surface area of potassium acetate is 40.1 Armstrong square. 


Preparation of Potassium Acetate

Potassium Acetate is prepared by a reaction known as an acid-base neutralisation reaction. While preparing potassium acetate, a potassium-containing base like potassium carbonate (\[ K_{2}Co_{3}\]) or potassium hydroxide (KOH) is treated along with the acetic acid. In a neutralisation reaction, a base is reacted with an acid to form salt and water. 


Potassium Acetate (Potassium ethanoate) is the salt that is formed along with water on the reaction of potassium hydroxide with acetic acid, which is neutralised together.


The reaction of the generation of potassium acetate is:-

\[CH_{3}COOH + KOH \rightarrow CH_{3}COOK + H_{2}O \]


Potassium Acetate can also be formed when a small volume of water is added along with potassium carbonate in the acetic acid solution, followed by crystallisation and evaporation.


The reaction formed is:-

\[ K_{2}Co_{3} + 2CH_{3}COOH \rightarrow  2CH_{3}COOK + H_{2}O + CO_{2}\]


In water, they form sesquihydrate at around a temperature range of 41.3°C, and then they eventually form semi hydrates.


Applications of Potassium Acetate

Potassium acetate salt has various applications in different fields. Potassium acetate is used in place of magnesium chloride and calcium chloride to remove ice and prevent its formation, that is, as a deicer. The use of potassium acetate is advantageous as it is less aggressive on soil and also less corrosive. Due to its advantages, potassium acetate is also used in airport runways even though it is more expensive.


The class K fire extinguishers also use potassium acetate salts in the form of an extinguishing agent due to their capability of forming a crust over burning oils and cooling it down.


Potassium acetate is an approved food preservative, food additive, and acidity regulator approved for its usage in Australia, the USA, and New Zealand. It is also used in agricultural and laboratory chemicals.


It is also used in the field of medicine for the treatment of diabetic ketoacidosis as a part of electrolyte replacement protocol. Potassium acetate is used due to its ability to break bicarbonates and aid in neutralising the acidotic state. During diabetic ketoacidosis, the potassium level in the blood decreases. So, the anion acetate present in the potassium acetate can be used as it increases the level of potassium salt to normal through the process of replacement in the neutralisation of metabolites.


The formaldehyde-based methods in the museums also use potassium acetate.


Potassium acetate is also used in the laboratory of molecular biology during the protocol of extraction of DNA because of its ability to precipitate bounded proteins and dodecyl sulphate. 


Also, potassium acetate is used in the processes of tissue preservation, mummification, and fixation. It is also used in the production of polyurethanes in the form of a catalyst and to precipitate dodecyl sulphate.


Fun Facts

  1. Potassium Acetate is used in the initial stages of the production of the first organometallic compound, also known as Cadet's fuming liquid. The compound was used as a diuretic and urinary alkaliser. The function of the compound is to change the physical properties of the body fluids.

  2. In the production of polyurethanes, potassium acetate is used as a catalyst.

  3. Potassium Acetate is related to health effects as it can be an irritator for the mucous or the eyes.

FAQs on Potassium Acetate

1. Is potassium acetate considered base or acid?

Potassium Acetate is a salt that is formed by an equal number of acetate ions and potassium ions. Potassium ion comes from a strong base named potassium hydroxide, and acetate ion comes from a weak acid named acetic acid. Potassium acetate is a conjugate base of acetic acid which is a weak acid. If the salt contains cations and anions that came from a strong base and acid, in that case, there is no effect on pH. Hence, there is no effect on pH by potassium ions but pH is affected by acetate ions.

2. What is Potassium Acetate Used?

Potassium Acetate uses are as follows:

  • Potassium Acetate is used in agricultural and laboratory chemicals.

  • It is used as a food preservative, food additive, and acidity regulator.

  • It is used in molecular biology applications like fixation and mummification as well as in DNA purification and to precipitate dodecyl sulfate.

  • It is used as a buffer and is also used instead of chloride salts to remove ice and stop its production.

  • It is used in fire suppression and in the making of lubricants.

  • The salt is used for ethanol precipitation of DNA.

3. What are the chemical and physical properties of potassium acetate?

The computed physical and chemical properties of potassium acetate are that the molecular weight of potassium acetate is 98.14, the number of hydrogen bond donors is 0, the number of hydrogen bond acceptors is 2 and the number of rotatable bonds is 0. The topological polar surface area of potassium acetate is 40.1 Armstrong square. There are 5 heavy atoms in potassium acetate and 0 formal charges. Potassium acetate is a canonicalized compound. The experimental physical and chemical properties of potassium acetate are that the compound is a dry powder, colorless, odorless, and exists in the form of deliquescent crystals or white crystalline powder. Potassium acetate has a faint acetic smell. The melting point of potassium acetate is 292 degrees celsius and the solubility of potassium acetate in water is 100g/ml at 20 degrees celsius. The density of potassium acetate is 1.6 g/ cm square and the pH of the compound is 7.5 to 9.0.

4. How can we prepare potassium acetate?

The preparation of potassium acetate is a simple method in the laboratory. The potassium acetate can be prepared by reacting acetic acid with a potassium-containing base (for example, potassium carbonate, potassium hydroxide) in an acid-base neutralization reaction. The neutralization reaction of acetic acid with potassium-containing compounds results in the formation of salt potassium acetate along with water. The preparation process can be represented in the form of the following chemical equation:


\[ CH_{3}COOH + K_{2}CO_{3} \rightarrow  CH_{3}CO_{2}K + CO_{2} + H_{2}O \]


The process of production of acetate requires environmental conditions that do not have heat, moisture, ignition sources, flames, and strong oxidizing agents.

5. How can I prepare a stock solution of 5 M 100 ml potassium acetate for use in the laboratory?

The stock solutions are the ones that are prepared in bulk and stored in the laboratory, those who require the solution can take an amount of stock solution and prepare their required working solution. 


To prepare a 5 M potassium acetate stock solution, you will first need to measure 49.07 gm of potassium acetate and dissolve it in 70 ml distilled water. When the complete salt of potassium acetate is dissolved, make the volume of the solution to 100 ml. Now, sterilize the stock solution in an autoclave for 15 mins after which you can use it for your laboratory experiments. 


Another method of preparing this solution in the laboratory is to dissolve 294.42 g of potassium acetate in 100 ml of water. Now adjust the pH of the solution to 4.6 by adding glacial acetic acid. Approximately, 40 - 50% of the total volume will be glacial acetic acid. Now, once your pH is set bring the to volume 1 liter (supposedly, 1 liter is your final volume). For preparing accurate solutions, your measurements should be accurate and you should set the pH of the solution adequately.