2K+H2SO3--->K2SO3+H2
H2SO3+2KOH--->K2SO3+2H2O
2H+ +SO3 2- +2K+ +2OH- --->2K+ +SO3 2- +2H2O
2H+ +2OH- --->2H2O
SO2+2KOH--->K2SO3+H2O
H2SO3+K2O--->K2SO3+H2O
