Question

1.P2O3-P2O5-Na3PO4-Ca3(PO4)2
2.Mg-MgO-Mg(OH)2-MgSO4

Answer 1

2) 2Mg + O2 = 2MgO

  MgO + H2O = Mg(OH)2

 Mg(OH)2 + H2SO4 = MgSO4 + 2H2O