Some Important Compounds of Sodium

Introduction

Sodium is one of the most important elements of group 1 of the periodic table. It is a very soft metal with silvery-white in color. Sodium is one of the most common alkali metals and the sixth most abundant element found on earth. 

This chapter contains all the theory portions with formation and mechanisms of sodium and its compounds. If you want to score good marks in examinations, then read these notes before appearing for the exam. 

Properties and production

As sodium is highly reactive, it doesn’t occur in a free state on earth. It was firstly prepared in the year 1807  by Sir Humphry Davy. It experimented by applying electrolysis to sodium hydroxide. Sodium occurs in many silicate materials such as micas, and feldspars. You can find huge deposits of rock salt in various parts of the world. At room temperature, sodium can be cut with a knife as it is lighter than water. But at low temperatures, it becomes brittle. It conducts electricity and heat and also exhibits a photoelectric effect. 

Most of the processes using sodium involve the electrolysis of molten sodium chloride. The element is used to produce gasoline additives, polymers, and several metals such as titanium, tantalum, and silicon. It is commonly used in sodium vapor lamps and as a heat exchanger.

Significant uses of sodium element

The two most important uses of metallic sodium are in the manufacture of sodium peroxide and sodium cyanide. Also used in making tetraethyl but in a significant quantity. Considerable amounts of sodium are generally used to manufacture sodium alkyl sulfates that are used as a principal ingredient for synthetic detergents.

Sodium also is used as one of the starting materials in the making of sodium hydride (NaH) and sodium borohydride (NaBH4). Adding to this, sodium is also used in the making of dyes and dye intermediates, in the synthesis of perfumes, and a wide variety of organic reductions. It is also used in the process of purification of hydrocarbons and the polymerization of unsaturated hydrocarbons. Sodium is used in its dispersion form in many organic applications.

It also has several applications in metallurgy. It is used as a reducing agent for the preparation of zirconium, calcium, titanium, and other transition metals. Molten sodium also has many applications. It is an amazing heat-transfer fluid, and, due to this, it is used as a coolant in liquid-metal fast breeder reactors. 

Compounds of Sodium 

As sodium is highly reactive with other elements, it forms many useful compounds which are compounds of sodium. In reaction with other metals, it forms compounds such as nitrate, sulfate, halides, carboxylates, and carbonates. 

Let’s study each sodium compound in detail.

Sodium Carbonate

Sodium carbonate is widely called washing soda. Its molecular formula is Na2CO3.10H2O. It is highly soluble in water. When we heat sodium carbonate, it converts into an anhydrous form. Sodium carbonate is synthesized by using sodium chloride and calcium carbonate during the formation of Solvay. 

Let’s see how we can form sodium carbonate in easy processes. 

How to form sodium carbonate? 

Following are the steps-

1. At first,  sodium chloride reacts with ammonia, carbon dioxide, and water which leads to the formation of sodium bicarbonate. The reaction is given below- 

NaCl + CO2 + NH3 +H2O →NaHCO3 + NH4Cl

2. At the second step, you will get  calcium oxide and calcium carbonate from calcium carbonate as shown in the following reaction. 

CaCO3 → CO2 + CaO

3. Now, sodium bicarbonate reacts with carbon oxide to form ammonia, calcium chloride, and water which is shown in the following reaction

2NH4Cl + CaO →CaCl2 + H2O

4. At last, sodium bicarbonate breaks down into sodium carbonate.

2NaHCO3 →Na2CO3 + H2O + CO2

Sodium Chloride 

Sodium chloride is the most famous and most used compound of sodium as common salt. It can be gained by the evaporation of seawater. Furthermore, sodium chloride can be obtained with the help of crystallization of brine solution which contains sodium sulfate, calcium sulfate, calcium chloride, and magnesium chloride.

Sodium Hydroxide 

Sodium hydroxide is commonly used as caustic soda. The process of its formation is known as Castner- Kellner cell. It can be obtained using two processes- the causticizing process and the electrolytic process.

1. a) Causticizing Process (Gossage process)- The process involves adding milk of lime to dilute sodium carbonate solution on heating it at 800 – 8500 The reaction is shown below-

Na2CO3   + Ca(OH)2  → CaCO3 + 2 Noah

2. b) Electrolytic Process – Brine solution is electrolyzed in this process which gives rise to two byproducts – H2 and Cl2. the reaction is shown below-

Ionization – Na+Cl-   → 2 Na+  +  2 Cl- 

At cathode – 2H2O + 2e-   →  2 OH- + H2        2 Na+ + 2OH-   → 2 NaOH (aq)

 At anode: 2Cl-  →Cl2+ 2 e –                    4 OH –   →  2 H2O   +  O2   +  4 e –

Sodium Hydrogen Carbonate

Sodium hydrogen carbonate is commonly used as baking soda that we use in baking and cooking. Its molecular formula is NaHCO3. Its decomposition leads to the formation of carbon dioxide. Sodium hydrogen carbonate is formed due to the reaction of sodium carbonates and carbon dioxide. The reaction is shown below- 

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

Uses of Sodium Compounds 

Compounds of sodium are widely used in many industries such as petroleum and textile. Let’s see some of its uses.

• Sodium chloride (NaCl) is commonly used as common salt. It is used in cooking and baking. It adds taste to the food. It is also used as a preservative for various packed food items. Sodium chloride can fight microorganisms and make your food healthy for a certain period. 

• Sodium Bisulfite is used to get rid of stubborn stains. 
• There are some other sodium compounds such as sodium carbonate (washing soda), caustic acid (sodium hydroxide), sodium nitrate (used in manufacturing and fertilizers),  and sodium thiosulfate that has several industrial uses. 

• Sodium Amalgam (an alloy of mercury and sodium) is used in fluorescent lamps as it produces sodium vapor for required illumination. These types of fluorescent lamps consume less power and produce yellow light.  

• Sodium Hydrogen Carbonate can be easily found in households and bakeries as it is used in food items. Sometimes, it is also used as an antiseptic during skin infections.
• Sodium Hydroxide is used in the preparation of oils and fats. It also has an application in the process of refining petroleum.

• Sodium Carbonate is used for cleaning, water softening, and laundering purposes. It is also used during the manufacturing of borax, glass, soap and caustic soda.

Conclusion

Sodium is an important element in the periodic table that has many useful compounds.  It is widely used in many forms. The most useful compound of sodium is sodium chloride which is commonly used as salt. Compounds of sodium have numerous applications in industries.