Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Calcium hydroxide (Ca(OH)2) is an alkaline compound made up of calcium ions (Ca2+) and two hydroxide ions (OH-) per formula unit. It dissociates in water to release these ions.
Related terms
Alkaline: Alkaline substances have pH values greater than 7, indicating they are basic rather than acidic.
Dissociation refers to the separation of a compound into its constituent ions when dissolved in a solvent, such as water. In the case of Ca(OH)2, it dissociates into calcium and hydroxide ions.
Formula Unit: A formula unit represents the simplest whole number ratio of ions present in an ionic compound. In the case of Ca(OH)2, one formula unit consists of one calcium ion and two hydroxide ions.