Select each side of the mass balance equation for an Fe3(PO₄)2 solution where the species in solution are Fe2, PO₃-4, HPO²⁻4, H2PO-4, H₃PO₄, and FeOH?
1) Fe3(PO₄)2 = Fe2 + 2PO₃-4
2) Fe3(PO₄)2 = FeOH + 2HPO²⁻4
3) Fe3(PO₄)2 = Fe2 + 2H2PO-4
4) Fe3(PO₄)2 = FeOH + 2H₃PO₄