Page 198 - Encyclopedia of Chemical Compounds 3 Vols

–
Ca ++ –O H

O –

H

OTHER NAMES:
Calcium hydrate;
caustic lime; hydated
lime; slaked lime
FORMULA:
Ca(OH) 2
ELEMENTS: Calcium Hydroxide
Calcium, oxygen,
hydrogen
COMPOUND TYPE:
Inorganic base
OVERVIEW
STATE: KE
Calcium hydroxide (KAL-see-um hye-DROK-side) is a soft,
Solid
white odorless solid that occurs as granules or a powder. It has a
Y
slightly bitter, alkaline taste. Calcium hydroxide absorbs car-
74.09 g/mol
MOLECULAR WEIGHT: F
bon dioxide readily from the air, changing to calcium carbonate
(CaCO 3 ). For this reason, the compound often is contaminated
A
Not applicable; loses with the carbonate unless it is kept in tightly sealed containers.
MELTING POINT: C
water when heated to T Calcium hydroxide is a relatively inexpensive chemical and, for
become calcium oxide S that reason,isusedinproductionprocesses whereabase is
(CaO)
needed. Although calcium hydroxideisnot very solublein
BOILING POINT: water, a suspension of the finely divided powder in water can
Not applicable be made, a suspension known as limewater or milk of lime.
SOLUBILITY:
Slightly soluble in
HOW IT IS MADE
water; soluble in
glycerol Calcium hydroxide is produced by adding water to cal-
cium oxide (CaO). This reaction is highly exothermic and
must be carried out with some care to avoid loss of the
product through spattering.

CHEMICAL COMPOUNDS 147