H2+Cl2--->2HCl
FeS+2HCl--->FeCl2+H2S
H2+S--->H2S
SO3+H2O--->H2SO4
N2O5+H2O--->2HNO3
P4O10+6H2O--->4H3PO4
Na2O+H2O--->2NaOH
2K+2H2O--->2KOH+H2
CuCl2+2NaOH--->Cu(OH)2↓+2NaCl
2NaOH+H2SO4--->Na2SO4+2H2O
Mg+2HCl--->MgCl2+H2
MgO+2HCl--->MgCl2+H2O
2Na+S--->Na2S
Ca(OH)2+2HNO3--->Ca(NO3)2+2H2O
2Ca+O2--->2CaO
CH4+2O2--->CO2+2H2O
2Fe+3Cl2--->2FeCl3
Ca+Cl2--->CaCl2
BaCl2+Na2SO4--->BaSO4↓+2NaCl
K2O+2HNO3--->2KNO3+H2O