General Knowledge



Symbol: Ca,
Atomic Number — 20,
Mass Number — 40

Physical and Chemical Properties :
This is a white metal like silver and it is soft when compared with the other metals but hard when compared with lead, whose relative density is 1.55. This metal also exhibits the phenomenon of malleability and ductility.

» The boiling point and melting point of this metal are 851°C and 1439°C.

Uses :
This metal is used in removing water which is present in small amounts in alcoholic solution. It is also used in removing elements like nitrogen, sulphur, and oxygen, which are present in small amounts during the process of metal extraction.

Compounds of Calcium

Calcium Oxide (CaO) :
This is also called quick lime. This is basically a white porous solid substance that reacts rapidly with water and calcium hydroxide is formed.

Calcium Hydroxide [Ca(OH)2] :
This is also called slaked lime, and it is obtained by reacting quick lime (CaO) with water.

Calcium Chloride (CaCl2) :
This occurs in a very small amount in sea water and ocean. It is basically a colourless, crystalline solid substance in which each molecule has six crystals of water.

Bleaching Powder [Ca(OCl)Cl]:
This is an oxychloride of calcium, and it is produced on large scale by Hasen Clever’s process. It is an extremely temporary compound used in bleaching action of paper and cloth or garment. This is also used as an insecticide or a germicide, as a water purifier, and as an anti-infective agent.