The solubility product constant of M₂CrO₄(s)is 7.11 × 10^-15.How many moles of M₂CrO₄(s)will dissolve in 744 mL of aqueous solution in which [CrO₄^2-] = 0.056 M?

Question

Quizplus · Accepted Answer

The solubility product constant expression is: Ksp = [M][CrO4]² We know that Ksp = 7.11 × 10⁻¹⁵ and [CrO4] = 0.056 M. Let's assume that x mol of M₂CrO₄(s) dissolves in aqueous solution, so its concentration is also x M. Then we have: 7.11 × 10⁻¹⁵ = (x)(0.056)² x = 1.8 × 10⁻⁷ mol/L Now we want to know how many moles will dissolve in 0.744 L (since 744 mL = 0.744 L): moles = (1.8 × 10⁻⁷ mol/L)(0.744 L) = 1.34 × 10⁻⁷ mol ≈ 1.8 × 10⁻⁷ mol Therefore, the best choice is B.

The Solubility Product Constant of M2CrO4(s)is 7

The Solubility Product Constant of M₂CrO₄(s)is 7