Calcium Hydroxide or Ca(OH)2 is called a base and is soluble in water. This means that in the solution with water, Calcium hydroxide splits into ions. It is more proper to say that Calcium hydroxide is soluble in water than react with water. The equation for the formation of ions when Calcium hydroxide is dissolved in water can be written as:
`Ca(OH)2 (aq) -> Ca^(2+) (aq) + 2OH^(-1) (aq)`
Upon the formation of hydroxide ions `( OH^(-1) )` , the solution now is classified basic.