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
Potassium Acetate is a deliquescent white crystalline solid which is insoluble in organic solvents like ether, but soluble in both alcohol, ammonia, and water.
Pure Potassium Acetate has a faint acetic smell, or we can say it is odourless, which has a saline taste.
It is used as a dehydrating and analytical agent in the manufacturing of crystal glasses and medicines.
Potassium acetate is a canonicalised compound. There are five heavy atoms in potassium acetate and 0 formal charges.
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
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.
The solubility of potassium acetate in water is 100g/ml at 20 degrees celsius.
The Potassium Acetate formula is \[CH_{3}CO_{2}K\] and has a molar mass of 98.142g/mol.
Potassium Acetate density is 1.8 grams per cubic centimetre.
The potassium Acetate melting point is 292°C.
Potassium Acetate has a higher boiling point and decomposes at a higher temperature.
The pH value of diuretic salt lies between 7.5 - 9.0.
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
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.
In the production of polyurethanes, potassium acetate is used as a catalyst.
Potassium Acetate is related to health effects as it can be an irritator for the mucous or the eyes.
FAQs on Potassium Acetate
1. What is potassium acetate?
Potassium acetate, also known as potassium ethanoate, is the potassium salt of acetic acid. Its chemical formula is CH₃COOK. It is formed from the reaction of a strong base (potassium hydroxide) and a weak acid (acetic acid), making it a key compound in understanding salt chemistry.
2. What are the main physical and chemical properties of potassium acetate?
Potassium acetate has several distinct properties that are important for its applications:
- Appearance: It is a white, crystalline powder or deliquescent crystal, meaning it readily absorbs moisture from the air.
- Odour and Taste: It is generally odourless or has a faint acetic smell with a saline taste.
- Solubility: It is highly soluble in water and alcohol but insoluble in solvents like ether.
- Melting Point: It has a high melting point of 292°C.
- pH: An aqueous solution of potassium acetate is alkaline, with a pH typically between 7.5 and 9.0.
3. How is potassium acetate prepared in the laboratory?
Potassium acetate is typically prepared through an acid-base neutralisation reaction. This involves treating acetic acid (CH₃COOH) with a potassium-containing base, such as potassium hydroxide (KOH) or potassium carbonate (K₂CO₃). The reaction with potassium hydroxide is as follows:
CH₃COOH + KOH → CH₃COOK + H₂O
The products of this reaction are potassium acetate salt and water.
4. Why is an aqueous solution of potassium acetate considered alkaline?
An aqueous solution of potassium acetate is alkaline due to a process called salt hydrolysis. The salt is formed from a weak acid (acetic acid, CH₃COOH) and a strong base (potassium hydroxide, KOH). In water, the acetate ion (CH₃COO⁻) reacts with water to form acetic acid and hydroxide ions (OH⁻). This increase in the concentration of OH⁻ ions makes the solution basic, or alkaline, with a pH greater than 7.
5. What are the major industrial and commercial uses of potassium acetate?
Potassium acetate is a versatile compound with several important applications:
- De-icing Agent: Used on airport runways as it is less corrosive than chloride salts.
- Fire Suppression: It is the primary agent in Class K fire extinguishers for combating fires from cooking oils and fats.
- Food Additive: It is used as a preservative and acidity regulator, identified by the E number E261.
- Medicine: It serves as an electrolyte in treatments for conditions like diabetic ketoacidosis.
- Molecular Biology: Used in the precipitation and purification of DNA.
6. Why is potassium acetate effective in Class K fire extinguishers?
Potassium acetate is highly effective for Class K fires (involving cooking oils and fats) because it creates a cooling and smothering effect. When sprayed onto the burning oil, it undergoes saponification, forming a thick, soapy foam layer. This foam crust cools the fuel below its ignition temperature and cuts off the oxygen supply, preventing re-ignition and extinguishing the fire efficiently.
7. How does potassium acetate work as a de-icer, and why is it preferred over common salt (NaCl)?
Potassium acetate works as a de-icer by lowering the freezing point of water, preventing ice from forming. It is often preferred over sodium chloride (NaCl) for sensitive applications like airport runways for two main reasons: it is significantly less corrosive to metals like aluminum used in aircraft, and it is less damaging to soil and vegetation, making it a more environmentally friendly choice.
8. What are the products of the electrolysis of an aqueous solution of potassium acetate?
The electrolysis of a concentrated aqueous solution of potassium acetate is an example of the Kolbe's electrolysis reaction. During this process, different products are formed at the electrodes:
- At the anode (positive electrode), ethane gas (C₂H₆) and carbon dioxide (CO₂) are produced.
- At the cathode (negative electrode), hydrogen gas (H₂) is evolved, and potassium hydroxide (KOH) is formed in the solution.
