1) 4Na+O2=2Na2O Na2O+H2O=2NaOH NaOH+HCl=NaCl+H2O NaCl+AgNO3=NaNO3+AgCl 2) 4P+5O2=2P2O5 P2O5+3H2O=2H3PO4 2H3PO4+3Ca(OH)2=Ca3(PO4)2+6H2O