The s-Block Elements

Some Important Compounds of Sodium and Potassium

Sodium and potassium salts are the better forms of  ‘common salt’. As much as it is difficult to imagine food without salts, these two elements find use in several industries. This makes them highly desired and useful elements found on planet earth. Let us get to know more about the compounds of sodium and potassium.

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Compounds of Sodium and Potassium

The compounds of sodium and potassium are as useful as the elements. They are very useful in industries. They have their unique properties. Before learning about the compounds of sodium and potassium. let’s learn about the elements first.

Compounds of Sodium and Potassium

Sodium (Na)

An alkali metal, Sodium belongs to Group 1. Sodium has an atomic number of 11. It usually manifests itself as a soft, white and highly reactive alkali metal. It has one electron in the outermost shell, upon losing which, it tends to form a sodium ion.  Sodium does not occur freely in nature as it is a highly reactive metal. You can store it in kerosene oil to prevent its reaction in the atmosphere and with the air. It mainly consists of three minerals such as sodalite, feldspar, and rock salt.

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Properties of Sodium

We know the following properties of sodium:

  • It is a highly reactive alkali metal.
  • Sodium appears yellow in the flame test.
  • Sodium has a soft texture, hence, it can be easily cut with a knife.
  • The melting and boiling points of sodium are lower than that of lithium.
  • Sodium possesses metallic bonding. It is also conducting in nature as it has one free electron.
  • It has lower first ionization energy.
  • The common oxidation state of sodium atom is +1

Uses of Sodium

Among the most common uses of Sodium in the human body are that it regulates the flow of water across the membrane and helps in transporting sugars and amino acids into various cells.

Potassium (K)

Potassium is an s-block element occurring in Group 1 below Sodium. It has an atomic number of 19. Hence its electronic configuration is ns1. It has one valence electron which it readily donates to accepting atoms. Hence, it forms strong ionic bonds and becomes a cation. The size of the cation of potassium is smaller than its atom since it loses its electron.

Potassium, like sodium, is a soft metal. It can be cut with a knife, It forms various compounds like salts, oxides, hydroxides, etc. Let’s study the compounds of sodium and potassium respectively now.

Important Compounds of Sodium

Some of the important compounds of Sodium are Sodium Carbonate, Sodium Chloride, Sodium Hydroxide, and Sodium Hydrogen Carbonate.

  • Sodium Carbonate: Sodium Carbonate, also commonly known as washing soda, has a molecular formula Na2CO3.10H2O. It is readily soluble in water. Heating of sodium carbonate decahydrate leads to the formation of sodium carbonate monohydrate. On further heating, monohydrate converts into an anhydrous form of sodium carbonate. It found uses in cleaning, softening, and laundering. It has found uses in the textiles industry. Sodium carbonate also supports the manufacture of glass, borax, soap, and caustic soda.
  • Sodium Chloride: As for Sodium Chloride, its main source is sea water. Crude sodium chloride is obtained by crystallization of brine solution, containing sodium sulphate, calcium sulphate, calcium chloride and magnesium chloride.
  • Sodium hydroxide: We commonly know caustic as sodium hydroxide. Among its many uses are manufacturing of soap, paper, artificial silk etc., used in textiles industries such as cotton industries, used as a precipitating agent in the laboratories and more.

Important Compounds of Potassium

The two most important compounds of Potassium are Potassium Fluoride and Potassium chlorides. Some other compounds of Potassium are as follows:

  • Potassium Permanganate: It is a dark purple crystal at room temperature. It is soluble in water. Its melting point is 240°C and density is 2.7 g/cm3. KMnO4 is a strong oxidizing agent. It is widely used to prevent infection, water purification etc.
  • Potassium Hypochlorite: Its formula is KClO and molar mass is 90.5507. We use it as a disinfectant.
  • Potassium Phosphate: It is a white powder at room temperature. It is soluble in water. Its melting point is 1380°C and density is 2.564 g/cm3. K3PO4 can be used as fertilizer or food additive.
  • Potassium Oxalate: It is a white crystal at room temperature. It is soluble in water. We use K2C2O4 mainly in the medical field e.g. as an anti-coagulant. It can also be used as a bleaching agent.
  • Potassium Chromate: It is a yellow powder at room temperature. It is soluble in water. Its melting point is 968 °C and density is 2.732 g/cm3. K2CrO4 can be used as an oxidizing agent.
  • Potassium Hydrogen Phthalate: It is a white solid at room temperature. It is soluble in water. Its melting point is 295 °C (563 °F) and density is 1.636 g/cm3. KHC8H4O4 can be used for pH meter calibration or as a buffering agent.
  • Potassium Hydrogen Carbonate: It is a white crystal at room temperature. It is soluble in water. Its melting point is 292 °C and density is 2.17 g/cm3. KHCO3 can be used in baking similar to soda. We can also use it as a pH regulator.

Question for You

Q: Discuss the properties of Sodium Hydrogen Carbonate and its uses.

Ans: Also known as baking soda, the molecular formula of Sodium Hydrogen Carbonate is NaHCO3. Upon decomposition, it leads to the formation of carbon dioxide, which you can understand through the equation:

2NaHCO3 (s)  CO2 (g) + H2O (g) + Na2CO3 (s)

You can use it as an antiseptic during a skin infection or in fire extinguishers. Most bakeries also make use of this compound to prepare and preserve pasties and cakes. It has a wide use across various industries.

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