Potassium Bicarbonate Formula: Definition & Properties

Potassium bicarbonate formula is \({\rm{KHC}}{{\rm{O}}_{\rm{3}}}{\rm{.}}\). It is an inorganic compound and is also known as potassium hydrogen carbonate or potassium acid carbonate. It appears as a white solid. It is the monopotassium salt of \({{\rm{H}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}\) (carbonic acid). It is rarely found in the mineral form kalicinite. In this article, we are going to discuss potassium bicarbonate in detail by covering its preparation, physical and chemical properties and uses. Read on to learn more about potassium bicarbonate.

Potassium Bicarbonate Chemical Formula

The chemical formula of potassium bicarbonate is \({\rm{KHC}}{{\rm{O}}_{\rm{3}}}{\rm{.}}\) It contains potassium \(\left( {{{\rm{K}}^{\rm{ + }}}} \right)\) and bicarbonate \(\left( {{\rm{HC}}{{\rm{O}}_{\rm{3}}}^{\rm{ – }}} \right)\) ions. It is considered as an ionic compound.

Potassium bicarbonate can be represented as,

The molar mass of potassium bicarbonate is \({\rm{100}}{\rm{.115\, g/mol}}{\rm{.}}\)

Potassium Bicarbonate Chemical Formula Derivation

The chemical formula of potassium bicarbonate can be derived using the criss-cross method. In the criss-cross method, if we know the valency of the constituent elements, we can write its formula. That is, the positive part’s symbol is written on the left and the negative part’s symbol is written on the right. The valency number of the positive part is written as the subscript on the symbol of the negative part and the valency number of the negative part is written as the subscript on the symbol of the positive part. Subscript one is not generally written. Signs of the charges are dropped.

Using this, the chemical formula of potassium bicarbonate can be written as,
Potassium bicarbonate contains potassium \(\left( {{{\rm{K}}^{\rm{ + }}}} \right)\) and bicarbonate \(\left( {{\rm{HC}}{{\rm{O}}_{\rm{3}}}^{\rm{ – }}} \right)\) radicals. The valency of potassium radical is one and that of bicarbonate radical is one. By criss-crossing these valency numbers, we can write the chemical formula of potassium bicarbonate as \({\rm{KHC}}{{\rm{O}}_{\rm{3}}}{\rm{.}}\) That is,

Preparation of Potassium Bicarbonate

Potassium bicarbonate is generally prepared using the following method:

By the Reaction of Potassium Carbonate Solution with Carbon Dioxide: When an aqueous solution of potassium carbonate is bubbled with carbon dioxide gas, potassium bicarbonate is formed. The chemical equation for the reaction can be given as,

\({{\rm{K}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}{\rm{ + C}}{{\rm{O}}_{\rm{2}}}{\rm{ + }}{{\rm{H}}_{\rm{2}}}{\rm{O}} \to {\rm{2KHC}}{{\rm{O}}_{\rm{3}}}\)

Properties of Potassium Bicarbonate

Let us discuss the physical and chemical properties of potassium bicarbonate.

Physical Properties of Potassium Bicarbonate

Potassium bicarbonate appears as white crystals. It is odorless too.
Potassium bicarbonate is soluble in water and is practically insoluble in alcohol.
The melting point of potassium bicarbonate is \({\rm{565\, K}}{\rm{.}}\) Above this temperature, it decomposes.
The density of potassium bicarbonate is \(2.17\, {\rm{ g/c}}{{\rm{m}}^{\rm{3}}}{\rm{.}}\)
Potassium bicarbonate is a hygroscopic solid. That is, it has the tendency to absorb moisture from the air.

Chemical Properties of Potassium Bicarbonate

1. Thermal decomposition of Potassium Bicarbonate: At higher temperatures, potassium bicarbonate decomposes to form potassium carbonate, carbon dioxide and water. The chemical equation for the reaction can be given as:

\(2{\rm{KHC}}{{\rm{O}}_{\rm{3}}} \to {{\rm{K}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}{\rm{ + C}}{{\rm{O}}_{\rm{2}}}{\rm{ + }}{{\rm{H}}_{\rm{2}}}{\rm{O}}\)

The above reaction is used for the preparation of high purity potassium carbonate.

2. Reactions of Potassium Bicarbonate: Different reactions given by potassium bicarbonate can be explained as:

(i) Reaction of Potassium Bicarbonate with Sulphuric acid: Potassium bicarbonate reacts with sulphuric acid to give potassium sulphate, water along with the evolution of carbon dioxide gas. The chemical equation for the reaction can be given as:

\({\rm{2KHC}}{{\rm{O}}_{\rm{3}}}{\rm{ + }}{{\rm{H}}_{\rm{2}}}{\rm{S}}{{\rm{O}}_{\rm{4}}} \to {{\rm{K}}_{\rm{2}}}{\rm{S}}{{\rm{O}}_{\rm{4}}}{\rm{ + 2C}}{{\rm{O}}_{\rm{2}}}{\rm{ + 2}}{{\rm{H}}_{\rm{2}}}{\rm{O}}\)

(ii) Reaction of Potassium Bicarbonate with Hydrochloric acid: Potassium bicarbonate reacts with hydrochloric acid to give potassium chloride and water along with the liberation of carbon dioxide gas. The chemical equation for the reaction can be given as:

\({\rm{KHC}}{{\rm{O}}_{\rm{3}}}{\rm{ + HCl}} \to {\rm{KCl + C}}{{\rm{O}}_{\rm{2}}}{\rm{ + }}{{\rm{H}}_{\rm{2}}}{\rm{O}}\)

Uses of Potassium Bicarbonate

Potassium bicarbonate has got many uses. They include:

In baking, potassium bicarbonate is used as a carbon dioxide source for leavening. Hence, it is used as a substitute for baking soda for the ones following a low sodium diet.
Potassium bicarbonate, as an inexpensive, non-toxic base, is commonly used as a reagent or pH regulating agent.
In club soda, potassium bicarbonate is used to improve the taste.
Potassium bicarbonate is used as a fire extinguisher.
It is also used as in condensed aerosol fire suppression.
Potassium bicarbonate is majorly used for the neutralization of acidic soil.
Against apple scab and powdery mildew, potassium bicarbonate acts as a fungicide. Hence, it is used in organic farming.
To produce more effervescence, potassium bicarbonate also used in winemaking.
Potassium bicarbonate is used as a mineral supplement to treat the low amounts of potassium mineral in the blood.
Potassium bicarbonate is also used as an antacid.
It is used as an electrolyte replenisher.
In drug formulations, it is used as an excipient.
It is used in photographic supplies, film, and photo chemicals
It can also be found in laundry and dishwashing products.
Potassium bicarbonate is used as plating and surface treating agents.

Summary

Potassium bicarbonate is an inorganic compound with the chemical formula \({\rm{KHC}}{{\rm{O}}_{\rm{3}}}{\rm{.}}\) It is the monopotassium salt of carbonic acid. It can be prepared by the action of carbon dioxide gas on potassium carbonate solution. It appears as white crystals. It is a hygroscopic solid. Potassium carbonate is considered as an ionic compound. The other physical and chemical properties and their several uses are well explained in this article.

FAQs on Potassium Bicarbonate Formula

Q.1. What is the formula of potassium bicarbonate?
Ans: Potassium bicarbonate is an inorganic compound with the chemical formula \({\rm{KHC}}{{\rm{O}}_{\rm{3}}}{\rm{.}}\)

Q.2. How can we write the chemical formula of potassium bicarbonate?
Ans: The chemical formula of potassium bicarbonate can be written using the criss-crosss method. Potassium bicarbonate contains potassium \(\left( {{{\rm{K}}^{\rm{ + }}}} \right)\) and bicarbonate \(\left( {{\rm{HC}}{{\rm{O}}_{\rm{3}}}^{\rm{ – }}} \right)\) radicals. The valency of potassium radical is one and that of bicarbonate radical is one. By criss-crossing these valency numbers, we can write the chemical formula of potassium bicarbonate as \({\rm{KHC}}{{\rm{O}}_3}.\) That is,

Q.3. What is potassium bicarbonate used for?
Ans: Potassium bicarbonate has several uses. It is used as a mineral supplement, fire retardant, used as antacid, chemical reagent, pH regulator, leavening agent, etc.

Q.4. Is potassium bicarbonate the same as baking soda?
Ans: Potassium bicarbonate is used as a substitute for baking soda because it has the exact leavening capabilities similar to that of baking soda.

Q.5. Is potassium bicarbonate good for humans?
Ans: Potassium bicarbonate is declared safe when used in permitted amounts by the Food and Drug Administration (FDA).

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