Question

What is the name for `Ca(OH)_2`?

Answer 1

Calcium hydroxide

Explanation:

The common name for it is quicklime - the term 'lime' comes from an old English word for 'sticky', as calcium compounds have been used to make mortar for many centuries. It is used amongst other things to cure acidity in soils, as it is a basic compound.

The reason the formula is as it is is that calcium ions have a 2+ charge whereas hydroxide ions have a single -ve charge and therefore you need two hydroxide ions to balance the charge of each calcium ion.