1) 2Mg+O2=2MgO
MgO+2HCl=MgCl+H2O
MgCl2+2NaOH=MgOH2+2NaCl
MgOH2+2HNO3=Mg(NO3)2+2H2O
2) 4P+5O2 = 2P2O5
P2O5 + 3H2O = 2H3PO4
H3PO4+KOH = K3PO4 +H2O
2K3PO4 + 3CaCl2 = Ca3(PO4)2 + 6KCl
3) 2Na +O2=Na2O2
Na2O+H2O=2NaOH
NaOH+HCL=NaCL+H2O
NaCL+H2SO4=NaHSO4+HCL