Question

What is the formal charge for the Phosphate Ion?

Answer 1

Phosphoric acid, `H_3PO_4`, can form phosphate salts, i.e. salts of `PO_4^(3-)`.

Explanation:

But in water, you would reach a stoichiometric endpoint at `"biphosphate"`, i.e. `HPO_4^(2-)`. See here.