Sodium is an alkali metal exists in Group 1 of the Periodic Table. The chemical formula of sodium is Na and its atomic number is 11. Sodium is the most common metal used as chemical products that are very soft in nature. Most importantly, it can be readily cut with a knife. Moreover, sodium is known as a good conductor of electricity. It is covered with a white coating of sodium hydroxide and sodium carbonate. Sodium can easily dissolve in cold water and give an alkaline solution. Sodium has many compounds that produce yellow colour when they burn.
Sodium is highly reactive and does not occur free in nature. So, to prevent its reaction in the atmosphere, it is kept in kerosene oil. It has one electron in the outermost shell that forms sodium ion on losing it. The three main minerals of sodium are sodalite, feldspar and rock salt which is commonly known as sodium chloride (NaCl).
Sodium and its compound are used commercially on a huge scale in different product industries like in glass, paper, soap and textile. The compound of sodium includes caustic soda (NaOH), table salt (NaCl), soda ash (Na2CO3), Sodium Nitrate (NaNO3), baking soda (NaHCO3), di/tri-Sodium Phosphates, Sodium thiosulfate (Na2B4O7.10H2O).
What are the uses of Sodium?
There are many uses of sodium in our daily life. It is mainly used to remove the impurities from molten metals and this ability of sodium makes it a more popular element among all. The process of manufacturing titanium metals from titanium tetrachloride (TiCl4) also uses sodium. Moreover, you can also separate metals like potassium and zirconium from their compound with the help of sodium. Sometimes certain alloys require improvement in their structure like smoothening which can be effectively done by metallic sodium. Sodium is also an excellent drying agent. Separating water from any liquid solution is not an easy task but this can be readily done with the help of sodium when combined with benzophenone. When it comes to preparing different chemical compounds like sodium peroxide, sodamide and sodium hydride, sodium is used. On the other hand, in reduction of organic esters, sodium is the first choice for the same.
What are the properties of Sodium?
There are two types of properties of sodium- physical and chemical properties.
Physical Properties of Sodium - Firstly, you need to know what physical properties are. The characteristics that can be detected without changing the substance into another substance are termed as physical properties. Usually, the properties that can be observed with the help of our senses such as colour, luster, freezing point, boiling point, density, melting point, hardness and odour are known as physical properties. Here we are discussing the physical properties of sodium.
• Reactive - Sodium is a highly reactive alkali metal.
• Softness - It is too soft and can be readily cut with the help of a knife.
• Color – The colour of sodium is silver-white.
• Conductivity – It is a good conductor of heat or electricity.
• Malleability – Sodium has the ability to being shaped and bent.
• Luster – It has a shiny and glowing outer.
Chemical Properties of Sodium – The characteristics that determine how it will react with other substance or change from one substance to another are called chemical properties. There is no option to analyze chemical properties with the sense. Furthermore, it can only be noticed during a chemical reaction such as burning, rusting, heating tarnishing, exploding etc.
Below are the chemical properties of sodium.
• Flammability - It burns with a brilliant golden- yellow flame.
• Oxidation – It gets merged with oxygen at room temprature.
• Formula – Chemical formula of Sodium is Na.
• Reactivity –
Water- It does react explosively and violently with water.
Acids – It produces hydrogen gas when it reacts with acids and also forms sodium amalgam when dissolved in mercury.
• Melting and boiling point- The melting and boiling point of sodium are lower than that of lithium.
Compounds of Sodium
Sodium is readily and frequently reacted with other elements that form other useful compounds. There form water-soluble compounds like halides, sulfate, nitrate, carboxylates, and carbonates but there are also many insoluble sodium compounds that are only found in nature like Sodium Bismuthate (NaBiO3), Sodium Octamolybdate (Na2MO8O25.4H2O), sodium thioplatinate (Na4Pt6S6) and sodium uranate (Na2UO4).
Sodium carbonate is commonly known as washing soda which has molecular formula Na2CO3.10H2O. This component is easily soluble in water. When heating, sodium carbonate decahydrate formats sodium carbonate monohydrate but it can convert into an anhydrous form on further heating. During the process of Solvay, sodium carbonate is synthesized by using sodium chloride and calcium carbonate.
How to form sodium carbonate?
Below are the steps for the formation:
1. Firstly, sodium chloride reacts with ammonia, carbon dioxide and water to form sodium bicarbonate.
NaCl + CO2 + NH3 +H2O →NaHCO3 + NH4Cl
2. Secondly, calcium carbonate is converted into calcium oxide and calcium carbonate.
CaCO3 → CO2 + CaO
3. In the third step, sodium bicarbonate reacts with carbon oxide to form ammonia, calcium chloride, and water.
2NH4Cl + CaO →CaCl2 + H2O
4. Finally, sodium bicarbonate decomposes into sodium carbonate.
2NaHCO3 →Na2CO3 + H2O + CO2
The most common method to obtain sodium chloride is the evaporation of sea water. Moreover, with the help of crystallization of brine solution, containing sodium sulfate, calcium sulfate, calcium chloride, and magnesium chloride, crude sodium chloride is obtained.
Sodium hydroxide is also known as caustic soda and its formation is known as a caster-Kellner cell. Sodium hydroxide is formed by two methods i.e. electrolytic and causticizing process.
a) Causticizing Process- This process is also referred as gossage process and it is obsolete nowadays. In this process, the milk of lime is added to dilute sodium carbonate solution while heating it at 800 – 850 C. Below is the reaction that takes place.
Na2CO3 + Ca (OH) 2 → CaCO3 + 2 Noah
b) Electrolytic Process – in this process, brine solution is electrolysed. H2 and Cl2 are two by-products of electrolytic process. One of the component (caustic soda) prepared with the help of this method is very poor.
Lionisation - Na+Cl- → 2 Na+ + 2 Cl-
At cathode - 2 H2O + 2 e- → 2 OH- + H2 2 Na+ + 2 OH- → 2 NaOH (aq)
At anode: 2 Cl- →Cl2 + 2 e - 4 OH - → 2 H2O + O2 + 4 e -
Sodium Hydrogen Carbonate
Sodium hydrogen carbonate is also known as baking soda that has a molecular formula of NaHCO3. Its decomposition forms carbon-dioxide. When sodium carbonates combine with carbon-dioxide it forms sodium hydrogen carbonate.
2 NaHCO3(s) CO2 (g) + H2O (g) + Na2CO3(s)
Uses of Sodium Compounds
Sodium compounds have a wide variety of uses, although sodium has limited uses. Various industries use sodium compounds on a large scale to manufacture products like soap, petroleum, chemicals, textiles, and paper. It has been an important part of the whole process. For example, sodium salts and fatty acids are combined together to make bathing and cleaning soap.
Sodium chloride (NaCl) is the most widely used sodium compound which is also known as table salt. Mainly it is used in cooking as a flavour-enhancer and also adds taste to the food. For baking, baking soda is used which is the combination of sodium and bicarbonate. Sodium chloride is also used as a preservative of various commercially packaged foods because sodium chloride has the ability to fight with microorganism and make your food healthy for a certain period.
Another compound of sodium is Sodium Bisulfite that is an excellent element to get rid of stubborn stains. Apart from these elements, there are some other sodium compounds like sodium carbonate (commonly known as washing soda), sodium nitrate (used in manufacturing fertilizers and smoke bombs), caustic acid (sodium hydroxide) and sodium thiosulfate that has numerous industrial uses.
Sodium Amalgam (an alloy of sodium and mercury) used in the fluorescent lamp, generates sodium vapour to provide the desired illumination. These lamps produce yellow light and consume less electricity. Due to this quality, they are considered as one of the most effective light sources and often seen as the first choice for street lighting.
Sodium Hydroxide is also one of the compounds of sodium that can be used during the preparation of fats and oils. On the other hand, it can be used during the refining of petroleum. A textile industry like cotton is the common place where the use of sodium chloride is observed.
Sodium Hydrogen Carbonate is commonly seen in houses and bakeries used to prepare pastries, cake etc. Apart from the kitchen usage, it can also be as antiseptic during skin infections. Sometimes in case of emergency, it is also observed using as a fire extinguisher.
Sodium Carbonate is especially used for water softening, cleaning and laundering purposes. During the manufacturing of glass, borax, soap and caustic soda sodium carbonate is used. Paint and textile industry also use sodium carbonate. It is also used in laboratories for qualitative and quantitative analysis.