Page 5 - Microsoft Word - Module-4

Properties:

 White amorphous powder.

 The aqueous solution is known as lime water and a

suspension of slacked lime in water is known as milk

of lime.

 When CO is passed through lime water it turns milky
2
due to the formation of CaCO .On passing excess
3

CO the ppt. dissolves to form Ca(HCO ) .
2
3 2
Ca(OH) +CO  CaCO +H O
2

2
2
3
CaCO +CO +H O  Ca(HCO )
3 2
2
2
3
 It reacts with Cl to form bleaching powder.
2
2Ca(OH) + Cl CaCl + Ca(OCl) +H O
2
2
2
2
2
(Bleaching powder)
Uses:

 Preparation of mortar and bleaching powder.

 Used in white wash and purification of sugar.

(c)Calcium Carbonate, CaCO :
3

Prparation:

Ca(OH) +CO  CaCO +H O
2

2
3
2
CaCl + Na CO  CaCO + 2NaCl
2
2
3
3