Strictly speaking, if we consider the concentration of OH- in the saturated solution of calcium hydroxide Ca(OH)2 at room temperature, it belongs to medium-strong alkali. However, due to its low solubility in water, the solute can not be completely dissolved, so its aqueous solution is still considered as a weak base in textbooks of high school and below.

Calcium hydroxide is a white powdery solid. Chemical formula Ca(OH) 2? Hydrated lime and hydrated lime are two layers after adding water, and the upper aqueous solution is called? Clear limewater, the lower suspension is called lime milk or lime slurry. The clear limewater in the upper layer can test carbon dioxide, and the turbid limewater in the lower layer is a building material. Calcium hydroxide is a white powdery solid, which is slightly soluble in water. Calcium hydroxide is a binary medium-strong alkali (it was considered as a strong alkali in middle school, but in fact it can't be completely ionized in water, so it is considered as a medium-strong alkali in college textbooks), which has the universality of alkali and has corrosive effects on skin and fabrics. Calcium hydroxide is widely used in industry. It is a common building material, and also used as bactericide and chemical raw material.

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Is calcium hydroxide a strong base or a weak base? Sogou asked [reference time 2018-1-15]