Phosphoric acid contains phosphate ions, PO43−\text{PO}_4^{3-}PO43−.
Phosphoric acid is completely neutralised by calcium hydroxide.
What is the formula of the salt that is made?
CaPO4\text{Ca}\text{PO}_4CaPO4
Ca2(PO4)3\text{Ca}_2(\text{PO}_4)_3Ca2(PO4)3
Ca3(PO4)2\text{Ca}_3(\text{PO}_4)_2Ca3(PO4)2
Ca3PO4\text{Ca}_3\text{PO}_4Ca3PO4