Question

Name the four chemicals that are obtained from common salt and write their molecular formulae.

Answer 1

Sodium chloride is a raw material that is used in the industrial manufacture of several chemicals. In the products, usually sodium cation remains and the chloride anion is replaced with some other anions.

Complete answer:
Common salt is sodium chloride. Its molecular formula is ${\text{NaCl}}$ . Sodium chloride is the main ingredient in our food. It is added to our food for taste and as a preservative.

We can obtain the following four chemicals from common salt.

Chemical name	Molecular formula
Sodium hydroxide or lye or caustic soda	${\text{NaOH}}$
Baking soda or sodium hydrogen carbonate or sodium bicarbonate	${\text{NaHC}}{{\text{O}}_{\text{3}}}$
Washing soda or sodium carbonate decahydrate	${\text{N}}{{\text{a}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}} \cdot 10{{\text{H}}_{\text{2}}}{\text{O}}$
Bleaching powder or calcium hypochlorite	${\text{CaOC}}{{\text{l}}_{\text{2}}}$

In the chlor alkali process, sodium hydroxide is prepared from common salt (sodium chloride). The byproducts are hydrogen gas and chlorine gas.Electrolysis of aqueous sodium chloride (brine solution) in Castner-kellner cell gives sodium hydroxide, chlorine gas and hydrogen gas.

In the Solvay process, limestone (calcium carbonate) ammonia, carbon dioxide and cold saturated aqueous sodium chloride solution produces sodium carbonate, sodium hydrogen carbonate and calcium chloride. Chlorine gas (obtained from chlor alkali process) reacts with dry slaked lime (calcium hydroxide) to form bleaching powder.

Note:
i) In the brick industry, you can use sodium carbonate as a wetting agent. In toothpaste, you can use sodium carbonate as a foaming agent and abrasive.
ii) We can use sodium hydrogen carbonate for pest control, as a disinfectant and in cooking, you can use sodium hydrogen carbonate for baking.
iii) We can use sodium hydroxide to manufacture paper, soaps and detergents. You can also use it to degrease metals.
iv) Bleaching powder is a strong oxidizing agent and disinfectant. It is used for bleaching dirty clothes in the laundry and in the textile industry, it bleaches linen and cotton.