Page 4 - Microsoft Word - Module-4

SOME IMPORTANT COMPOUNDS OF Ca

(a)Calcium Oxide or Quick lime (CaO):

It is prepared by heating limestone at 1273K.

CaCO CaO + CO
3
2
Properties:

 It is white solid having very high m.p of 2870K.

 It readily absorbs moisture and CO
2.

CaO + H O  Ca (OH)
2
2
CaO+ CO  CaCO
2
3
 Adding limited amount of water is called slacking of

lime and produces slacked lime.

 Quick lime mixed with soda (NaOH) gives soda.

 It combines with acidic oxide and acts as flux.

CaO + SiO CaSiO
2
3
Uses:
 Used as a drying agent for ammonia and sodalime.

 Used in manufacture of glass and cement and

purification of sugar.

(b)Calcium hydroxide (Slacked lime), Ca(OH) :
2

Prepared by adding water to quick lime.

CaO + H O  Ca (OH)
2
2