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 1.2 × 10^-10, 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

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Quizplus · Accepted Answer

BaCrO₄ will precipitate first due to its higher Ksp. When BaCrO₄ starts to precipitate, [CrO₄²⁻] = Ksp / [Ba²⁺] = 1.2 × 10⁻¹⁰ / 0.50 = 2.4 × 10⁻¹⁰ mol L⁻¹. For Ag₂CrO₄, [Ag⁺]² = Ksp / [CrO₄²⁻] = 1.1 × 10⁻¹² / 2.4 × 10⁻¹⁰ = 4.58 × 10⁻³, so [Ag⁺] = √4.58 × 10⁻³ = 6.8 × 10⁻² mol L⁻¹.

Solid Potassium Chromate (K2CrO4)is Slowly Added to a Solution Containing

Solid Potassium Chromate (K₂CrO₄)is Slowly Added to a Solution Containing