Question

Given a metal phosphate, `M_3(PO_4)_2`, what salt would this metal from with sulfate ion?

Answer 1

The corresponding metal sulfate would be `MSO_4`...........

Explanation:

Why?

We gots `M_3(PO_4)_2`; now phosphate anion is formally `PO_4^(3-)`, i.e. a salt of `"phosphoric acid"`, `H_3PO_4`. And in the given formula we have `2xxPO_4^(3-)`, a formal electronic charge of `-6`. Clearly, to form a neutral salt, the three metal ions must have a combined formal charge of `+6`, and given this we have `M^(2+)` ions.......

And thus the salt the metal forms with sulfate anion would be 1:1, i.e. `M^(2+)SO_4^(2-)`.