What is the PH of 0.40 M Na2SO3? (K1 for H2SO3 = 1.5 * 10^-2; K2 = 1.0 * 10^-7

Answer 1

.......SO3^2- HOH ==> HSO3^- + OH^-
I......0.4.............0........0
C......-x...............x.......x
E.....0.4-x.............x........x

Kb for SO3^2- = (Kw/K2 for H2SO3) = (HSO3^-)(OH^-)/(SO3^2-)
Substitute from the ICE chart, solve for x = OH^-, convert to pH.