18. Aqueous Equilibrium

Two mixtures are added into one flask at 25 °C, one mixture contains 0.55 mL of 0.75 M BaF₂ and another 0.25 mL of 1.3 M Mg(OH)₂. K_sp of Magnesium Fluoride, MgF₂, is 7.4 x 10⁻⁹. Identify the correct option.

a) MgF₂ solid will form

b) MgF₂ solid forms, along with Mg⁺² and F⁻ ions

c) solution is unsaturated, precipitate does not form

d) solution is saturated, precipitate forms

Ca1OH22 has a Ksp of 6.5 * 10-6. (b) If 50 mL of the solution from part (a) is added to each of the beakers shown here, in which beakers, if any, will a precipitate form? In those cases where a precipitate forms, what is its identity? [Section 17.6]

The following pictures represent solutions of Ag2CrO4, which also may contain ions other than Ag+ and CrO42- that are not shown. Solution 1 is in equilibrium with solid Ag2CrO4. Will a precipitate of solid Ag2CrO4 form in solutions 2-4? Explain.

(1) (2) (3) (4)

A solution of Na₂SO₄ is added dropwise to a solution that is 0.010 M in Ba²⁺(aq) and 0.010 M in Sr²⁺(aq). (a) What concentration of SO₄^2- is necessary to begin precipitation? (Neglect volume changes. BaSO₄: Ksp = 1.1⨉10^-10; SrSO₄: Ksp = 3.2⨉10^-7.)

A solution of Na₂SO₄ is added dropwise to a solution that is 0.010 M in Ba²⁺(aq) and 0.010 M in Sr²⁺(aq). (c) What is the concentration of SO₄^2-(aq) when the second cation begins to precipitate?