Question

Write the chemical name and formula of (a) common salt, and (b) caustic soda.

Answer 1

Hint: Common salt is the chloride salt of alkali metal. It is obtained from the evaporation of seawater. Caustic soda is a hydroxide salt of alkali metal. It is obtained from the electrolysis of common salt.

Complete step by step solution:
(a)
Common salt contains sodium which is an alkali metal and chloride ion. Sodium chloride is known as common salt. It is the common name of sodium chloride.
Common salt is used as table salt. It is also used for the preparation of sodium hydroxide, sodium carbonate or sodium peroxide.
So, the chemical name and formula of common salt is sodium chloride NaCl.

(b) Caustic soda is salt containing sodium which is an alkali metal and hydroxide. Sodium hydroxide is known as caustic soda. It is the common name of sodium hydroxide. Caustic soda is also known as a Lye.
Caustic soda is used for the preparation of soda lime. It is also used as a reagent in the laboratory. It is also used as a cleansing agent.
So, the chemical name and formula of caustic soda is sodium hydroxide NaOH.

Note: Both common salt and caustic soda are salts of sodium metal. The common salt is extracted by the crystallization of the brine solution. The main preparation methods of caustic soda are Nelson Diaphragm cell, Loewig’s method, and Castner Kellner method. In the Castner Kellner method, a brine solution is electrolyzed to get sodium hydroxide. Brine solution contains impurities like calcium and magnesium chloride, sulphate of calcium, and sodium. These impurities are filtered by dissolving the crude salt in water.