[meenu]

Barium Nitrate reacts with potassium sulphate and form insoluble Barium sulphate .What volume of 0.40 mol/L  of Ba(NO3)2 Solution is required to precipitate effectively the suphate ions in 25 ml of 0.80 mol / L  of K2SO4 solution .
given K sp of    BaSO4 = 1.1 x 10^ -10

[AWK]

Write down the stoichiometry of reaction. Assume just stoichiomentric amount of barium nitrate is sufficient to precipitate BaSO4 effectively (or use a specific criterion for effectivenes of precipitation, and then calculate an excessing of barium nitrate concnetration using Ksp to fullfill this criterion).