A saturated BaSO₄ solution is split into two equal portions. Portion A is adjusted to [Ba²⁺] = 0.020 M by adding Ba(NO₃)₂; portion B is adjusted to [SO₄²⁻] = 0.020 M by adding Na₂SO₄. Which portion will form a larger mass of additional BaSO₄ precipitate? Briefly justify your answer.