Calcium Hydroxide

Calcium Hydroxide
Other Names: Slaked lime, Milk of lime, Calcium(II) hydroxide, Pickling lime, Hydrated lime, Portlandite, Calcium hydrate, Calcium dihydroxide

CAS Number: 1305-62-0
Sum Formula: Ca(OH)₂
Molar Mass: 74.09 g/mol
Appearance: White powder or colorless crystalline solid

Calcium hydroxide is an inorganic compound formed by the hydration of calcium oxide (quicklime). It is a strong base and is widely used in construction, environmental treatment, and chemical manufacturing. In aqueous suspension, it forms a milky solution known as "milk of lime."

Chemical and Physical Properties
Density: 2.24 g/cm³
Melting Point: 580°C (decomposes)
Boiling Point: Not applicable (decomposes)
Solubility in Water: Slightly soluble (~1.65 g/L at 20°C), forms a basic solution (pH ≈ 12.4)
Solubility in Other Solvents: Insoluble in alcohol; soluble in acids and glycerol
Odor: Odorless

Applications
Construction: Used in mortar, plaster, and whitewash; essential in cement and lime production.
Water Treatment: Applied to neutralize acidic water and remove impurities.
Chemical Manufacturing: Intermediate in the production of calcium salts and organic base catalysis.
Agriculture: Used to correct soil acidity and as a disinfectant in farming.
Environmental Applications: Utilized in flue gas desulfurization and sewage treatment.

Safety

Signal Word: Warning

Handling and Storage
Storage Conditions: Store in tightly sealed containers in a dry, cool, and well-ventilated area. Protect from moisture and carbon dioxide, which can react with the substance to form calcium carbonate.
Handling Precautions: Avoid creating or inhaling dust. Use appropriate PPE and handle under good industrial hygiene practices.