Question

The ions Ca2+ and PO43- form salt with the formula

Answer 1

Ca3(PO4)2 is the answer.

Answer 2

Answer : The formula for the compound is
`Ca_3(PO_4)_2`

Explanation :

For formation of a neutral ionic compound, the charges on cation and anion must be balanced.

The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non-metals.

In the given question, the calcium metal forms an ionic compound with polyatomic anion (phosphate)
`PO_4^(3-)`.

Here, calcium is having an oxidation state of +2 called as
`Ca^(2+)` cation and phosphate
`PO_4^(3-)` is an anion with oxidation state of -3. The charges are not balanced. So, the charges are balanced by the cris-cross method. Thus, the compound formed will be,
`Ca_3(PO_4)_2`

Hence, the formula for the compound is
`Ca_3(PO_4)_2`