According to the Henderson s equation pOH pK log bisa NH4 2SO4 NH OH ele DOUG 2 4 7 log 4 7 pH 14 pOH 14 4 7 9 3 Its given that the final volume is 500 mL and this final volume was arrived when 50 mL of 1 M Na2SO4 was added to unknown Ba solution 2 2 So we can interpret the volume of unknown Ba solution as 450 mL i e 450mL 50mL 500mL Ba 2 BaSO4 solution solution From thi we can calculate the concentration of SO2 ion in the solution via DA Na2SO4 solution M V M V 1x 50 M x 500 as 1M Na SO4 is taken into consideration 1 M 0 1 M nongo and