Posted by Summer on .
What is the concentration of SO3^2 in a 0.043 M solution of Sulfurous acid (H2SO3) in water? The value of Ka1 for H2SO3 is 1.300 x 102 and the value of Ka2 is 6.300 x 108.

Chemistry 
DrBob222,
H2SO3 ==> H^+ + HSO3^
HSO3^ ==> H^+ + SO3^2
k1 is much larger than k2; therefore, H^+ is essentially equal to HSO3^. So we write
k2 = (H^+)(SO3^2)/(HSO3^)
Since (H^+) = (HSO3^), then
(SO3^2) = k2.