Question

A solution is made from 0.050 M BaCl2 and 0.025 M CaCl2. What concentration of 𝑆𝑂4 2− must be present to leave 99.99% of only one of the cations in solution? Ksp of BaSO4 = 1.10 x 10-10 and Ksp for CaSO4 = 2.4 x 10-5 .

Answer 1

K_sp BaSO₄ =

Concentration of Ba²⁺

× Concentration of SO₄^2- .

1.1 × 10^-10 = 0.05 × Concentration of SO₄^2- .

So, Concentration of SO₄^2- = 2.2 × 10^-9 .

K_sp of CaSO₄ = Concentration of Ca²⁺

× Concentration of SO₄^2- .

2.4 × 10^-5 = 0.025 × Concentration of SO₄^2- .

Concentration of SO₄^2- = 9.8 × 10^-4 .