Solid Potassium Chromate (K₂CrO₄) Is Slowly Added to a Solution

Multiple Choice

Solid potassium chromate (K₂CrO₄) is slowly added to a solution containing 0. 50 mol L^-1 AgNO₃ and 0. 50 mol L^-1 Ba(NO₃) ₂. What is the Ag⁺ concentration when BaCrO₄ just starts to precipitate? The K_sp for Ag₂CrO₄ and BaCrO₄ are 1.1 × 10^-12 and respectively.

A) 6.5 × 10^-5 mol L^-1
B) 1.3 × 10^-4 mol L^-1
C) 3.2 × 10^-4 mol L^-1
D) 6.8 × 10^-2 mol L^-1