So3+koh--> co2+ca(oh)2--> n2o5+> p2o5+ba(oh)2-->

1)SO3+2KOH=K2SO4+H2O
SO3+KOH=KHSO4+H2O

2)CO2+Ca(OH)2=CaCO3+H2O
2CO2+Ca(OH)2=Ca(HCO3)2
CO2+2Ca(OH)2=(CaOH)2CO3+H2O

3)N2O5+2LiOH=2LiNO3+H2O

4)P2O5+3Ba(OH)2=Ba3(PO4)2+3H2O
P2O5+2Ba(OH)2=2BaHPO4+H2O