Discuss the preparation and properties of sodium carbonate.
Answers
Sodium carbonate is an inorganic compound used as a moderate strength base. It is also called soda ash or washing soda.
Preparation: Sodium carbonate is obtained commercially through two different methods. The first method involves mining the mineral deposits of sodium carbonate, which is the main production method in the USA. In the second method, called the Solvay process, sodium chloride is reacted with ammonia to give sodium bicarbonate, which is then heated to give sodium carbonate.
Physical properties: Sodium carbonate is a white crystalline powder with a density of 2.54 g/mL, and a melting point of 851 °C.
Chemical properties: Sodium carbonate is a stable but hygroscopic solid (absorbs water from air) and readily dissolves in water to form weakly acidic carbonic acid and the strong base, sodium hydroxide. Thus, the aqueous solution of Na2CO3 is overall a strong base. It reacts violently with many acids. When heated to high temperatures, it decomposes to emit toxic fumes of disodium oxide (Na2O).