CaO+H2O=Ca(OH)2 SO2+CaO=CaSO3 H2O+SO2=H2SO3 2NaOH+SO2=Na2SO3+H2O ZnO+SO2=ZnSO3 ZnO+H2O=Zn(OH)2 ZnO+2HCL=ZnCL2+H2 CaO+2HCL=CaCL2+H2O NaOH+HCL=NACL+H2O