Calcium Hydroxide / Hydrated Lime

Calcium hydroxide, commonly called slaked lime or hydrated lime, is a versatile inorganic compound with the chemical formula Ca(OH)₂. It is a strong base produced by mixing calcium oxide (quicklime) with water in a heat-releasing reaction.

Composition and Common Names

Each molecule consists of one calcium atom bonded to two hydroxide groups. Its common names vary by industry:

• Slaked / Hydrated Lime: Reflects the hydration process used to create it.
• Builders’ Lime: Used in construction and masonry.
• Pickling Lime: Used for food preservation.
• Portlandite: Its rare, naturally occurring mineral form found in volcanic zones.

Physical and Chemical Properties

• Appearance: An odorless, white, fine powder.
• pH Level: Highly alkaline with a pH of approximately 12.4.
• Solubility: Sparingly soluble in water (1.73 grams per liter at 20°C). Its watery mixture is called limewater or lime putty.

Storage Requirements

To prevent degradation and reactions with atmospheric carbon dioxide, store it in:

• Airtight containers
• Dry environments
• Cool, shaded areas