Potassium Oxide Formula: Definition, Preparation, Uses

Potassium Oxide Formula: Potassium oxide is an inorganic compound. It is a highly reactive compound that is rarely encountered. The formula of Potassium Oxide is \({{\rm{K}}_2}{\rm{O}}\). It is an alkali metal oxide. It is the simplest oxide of potassium which is highly reactive in nature. It is an ionic compound composed of potassium and oxygen atoms. It is not used directly but is often used as a reagent in many instances. Potassium oxide is a metallic oxide that is basic in nature. In this article, we will discuss potassium oxide in greater detail.

Potassium Oxide Chemical Formula

The chemical formula of potassium oxide is \({{\rm{K}}_2}{\rm{O}}\).

It contains potassium and oxygen atoms. There exists an ionic bond between potassium and oxygen atoms. Therefore, it is an ionic compound. An ionic compound is formed by the transfer of electrons between the constituent atoms.

Formation of Potassium Oxide

The atomic number of potassium is \(19\). It has one electron in its outermost shell. Therefore, it can donate this electron to obtain a stable electronic configuration. Similarly, the atomic number of oxygen is \(8\). It has six electrons in its outermost shell. It needs two more electrons to complete its octet. Therefore, during the formation of potassium oxide, two potassium atoms transfer two (one electron each from one potassium atom) electrons to an oxygen atom to form an ionic bond between them. It can be represented as,

The molar mass of potassium oxide is \(94.196\;{\rm{g}}/{\rm{mol}}\).

The crystal structure of potassium oxide can be represented as,

Potassium Oxide Chemical Formula Derivation

The chemical formula of potassium oxide can be derived using the Criss-cross method.

In the criss-cross method, if we know the valency of each element of a compound, we can easily write its formula. The symbol of the positive part is written to the left-hand side and the symbol of the negative part to its right. The valency of each element is placed as a subscript on the side of the symbol of another element. Subscript \(1\) is not often written.

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Using this, the chemical formula of potassium oxide can be found as,

Potassium oxide contains potassium \(\left( {{{\rm{K}}^ + }} \right)\) and oxide \(\left( {{{\rm{O}}^{2 – }}} \right)\) ions. The valency of potassium ion is one and that of oxide ion is two. By criss-crossing these valency numbers, the chemical formula of potassium oxide is \({{\rm{K}}_2}{\rm{O}}\). That makes the formula for potassium oxide which is,

Preparation of Potassium Oxide (K₂O)

Potassium oxide can be prepared using the following methods:

1. Potassium oxide is formed when potassium is reacted with oxygen. The chemical equation for the reaction can be given as,

\(4\;{\rm{K}} + {{\rm{O}}_2} \to 2\;{{\rm{K}}_2}{\rm{O}}\)

During this reaction, potassium peroxide is also formed, which on treatment with potassium produces potassium oxide. That is,

\({{\rm{K}}_2}{{\rm{O}}_2} + 2\;{\rm{K}} \to 2\;{{\rm{K}}_2}{\rm{O}}\)

2. Potassium oxide can be produced conveniently by heating potassium nitrate with the potassium metal. The chemical equation for the reaction can be given as,

\(2{\rm{KN}}{{\rm{O}}_3} + 10\;{\rm{K}} \to 6\;{{\rm{K}}_2}{\rm{O}} + {{\rm{N}}_2} \uparrow \)

3. Potassium oxide is also produced when potassium peroxide is heated at \(500\,^\circ {\rm{C}}\). That is, potassium peroxide is decomposed to give potassium oxide and oxygen. The chemical equation for the reaction can be given as,

\(2\;{{\rm{K}}_2}{{\rm{O}}_2} \to 2\;{{\rm{K}}_2}{\rm{O}} + {{\rm{O}}_2} \uparrow \)

4. Potassium oxide is produced when potassium hydroxide is reacted with molten metallic potassium. The chemical equation for the reaction can be given as,

Properties of Potassium Oxide

Let us discuss the physical and chemical properties of potassium oxide \(\left( {{{\rm{K}}_2}{\rm{O}}} \right)\).

Physical Properties of Potassium Oxide

1. Potassium oxide appears as a pale-yellow solid.
2. Potassium oxide is an odourless compound.
3. Potassium oxide is readily soluble in diethyl ether.
4. The melting point of potassium oxide is approximately equal to \(1010\;{\rm{K}}\).
5. Potassium oxide is deliquescent (It is the property of a substance to absorb water from the air to dissolve itself and form an aqueous solution) in nature.

Study Potassium Hydroxide Formula

Chemical Properties of Potassium Oxide

1. Potassium oxide is a metal oxide. Metal oxides are generally basic or alkaline in nature. Therefore, potassium oxide is alkaline in nature and is highly corrosive too.

2. Potassium oxide is a deliquescent substance. Hence, it absorbs moisture vigorously from the air.
The reaction of potassium oxide with water produces potassium hydroxide. The chemical equation for the reaction can be given as,
\({{\rm{K}}_2}{\rm{O}} + {{\rm{H}}_2}{\rm{O}} \to 2{\rm{KOH}}\)

3. Potassium oxide, when heated above \(300\,^\circ {\rm{C}}\), decomposes to form potassium peroxide and potassium. The chemical equation for the reaction can be given as,

4. Reactions of Potassium Oxide with Acids:

The reaction of potassium oxide with different acids can be given as,

Reaction of Potassium Oxide With Sulphuric Acid

Potassium oxide reacts with sulphuric acid to form potassium sulphate and water. The chemical equation for the reaction can be given as,
\({{\rm{K}}_2}{\rm{O}} + {{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4} \to {{\rm{K}}_2}{\rm{S}}{{\rm{O}}_4} + {{\rm{H}}_2}{\rm{O}}\)

Reaction of Potassium Oxide with Hydrochloric Acid

Potassium oxide reacts with hydrochloric acid to give potassium chloride and water. The chemical equation for the reaction can be given as,
\({{\rm{K}}_2}{\rm{O}} + 2{\rm{HCl}} \to 2{\rm{KCl}} + {{\rm{H}}_2}{\rm{O}}\)

Reaction of Potassium Oxide with Nitric Acid

Potassium oxide reacts with nitric acid to give potassium nitrate and water. The chemical equation for the reaction can be given as,
\({{\rm{K}}_2}{\rm{O}} + 2{\rm{HN}}{{\rm{O}}_3} \to 2{\rm{KN}}{{\rm{O}}_3} + {{\rm{H}}_2}{\rm{O}}\)
Potassium oxide is basic in nature. Therefore, the reaction of potassium oxide with different acids are the example of neutralization reaction.

Uses of Potassium Oxide

Potassium oxide has got many uses. They include:

1. Potassium oxide is majorly used in fertilizers, cement formulas and in glassmaking formulas.
2. Potassium oxide is suitable for optic and ceramic applications.
3. It is used as a reagent for the manufacture of other chemicals.
4. It is used for the treatment of some fungal infections in the zygomycetes.

Summary

Potassium oxide is an inorganic compound with the chemical formula \({{\rm{K}}_2}{\rm{O}}\). It is formed when metallic potassium reacts with oxygen. Potassium oxide is generally alkaline in nature. Due to its deliquescent nature, it reacts very vigorously with moisture to form potassium hydroxide. It decomposes above the temperature of \(300\,^\circ {\rm{C}}\). In this article, we have explained the formula, other preparation methods, physical and chemical properties, and their major uses in detail.

PRACTICE QUESTIONS RELATED TO POTASSIUM OXIDE

FAQs on Potassium Oxide Formula

Here are some of the frequently asked questions related to Potassium Oxide Formula:

Q.1. What is the formula of potassium oxide?
Ans: Potassium oxide is an inorganic compound with the chemical formula \({{\rm{K}}_2}{\rm{O}}\). It is an ionic compound.

Q.2. What is potassium oxide used for?
Ans: Potassium oxide has got many uses. It is majorly used in fertilizers, cement formulas and in glassmaking formulas. Potassium oxide is suitable for optic and ceramic applications. It is used as a reagent for the manufacture of other chemicals, it is used for the treatment of some fungal infections in zygomycetes, etc.

Q.3. Is potassium oxide acidic?
Ans: No, potassium oxide is basic. It is a metal oxide. Generally, metal oxides are basic in nature.

Q.4. Is \({{\rm{K}}_2}{\rm{O}}\) ionic or covalent?
Ans: \({{\rm{K}}_2}{\rm{O}}\) is ionic. During the formation of potassium oxide, two potassium atoms transfer two (one electron each from one potassium atom) electrons to an oxygen atom to form an ionic bond between them.

Q.5. What happens when potassium oxide reacts with water?
Ans: The reaction of potassium oxide with water produces potassium hydroxide. The chemical equation for the reaction can be given as,
\({{\rm{K}}_2}{\rm{O}} + {{\rm{H}}_2}{\rm{O}} \to 2{\rm{KOH}}\)
The above reaction is a vigorous reaction.

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