Calcium hydroxide
Molar mass: 74.09 g/mol · Class: Strong base (sparingly soluble)
Elements: calcium, oxygen, hydrogen
Structure
The solid is an ionic lattice of Ca2+ ions and OH- ions. It dissolves only slightly in water, but the dissolved portion gives a strongly basic solution called limewater.
Properties
White powder, sparingly soluble in water
Solution (limewater) is strongly basic
Absorbs CO2 from air, turning milky then forming carbonate
Releases heat when made from calcium oxide
Applications
Mortar, plaster, and whitewash
Water treatment to reduce acidity
Food processing (nixtamalization, pickling lime)
Flue-gas desulfurization
Corrosive to eyes and irritating to skin and airways: the dust is caustic. Wear goggles and a dust mask when handling powder. Rinse skin contact with plenty of water.
Data source: IUPAC standard atomic weights 2021; molar mass computed from Ca(OH)2