Solubility Equilibrium and Ksp Practice Problems

Answer Key for Solubility Equilibrium

1A, 2C, 3B, 4C, 5A, 6C, 7C, 8B, 9A, 10D, 11D, 12A, 13B, 14C, 15C, 16D, 17B

Detailed Solutions for Solubility Problems

Problem 1: Net Ionic Equation and Precipitation

1a. Net Ionic Equation:
Pb²⁺ + 2Cl^- → PbCl₂(s)

1b. Precipitation Calculation:
moles Pb²⁺ = (0.0150)(0.0500) = 0.00075
moles Cl^- = (0.0350)(0.0850) = 0.002975
total volume = 0.0500 L

[Pb²⁺] = 0.00075 / 0.0500 = 0.0150 M
[Cl^-] = 0.002975 / 0.0500 = 0.0595 M

Q = [Pb²⁺][Cl^-]² = (0.0150)(0.0595)²
Q = 5.3 × 10^-5
K_sp = 1.6 × 10^-5
Since Q > K_sp, a precipitate indeed forms.

Problem 2: Calculating Ksp for Silver Sulfate

2a. K_sp of Ag₂SO₄:
moles = mass / molar mass
moles = (7.2 × 10^-4) / 311.8 = 2.31 × 10^-6 mol

s = moles / volume
s = (2.31 × 10^-6) / 0.0500 = 4.62 × 10^-5 M

K_sp = (2s)²(s) = 4(4.62 × 10^-5)³ ≈ 3.9 × 10^-13

Problem 3: Determining Mass of Sodium Iodide

Mass of NaI:
[I^-] = (1.1 × 10^-12) / (0.010) = 1.1 × 10^-10 M

moles I^- = M × V
moles I^- = (1.1 × 10^-10)(0.2500) = 2.75 × 10^-11 mol

mass NaI = moles × molar mass
mass NaI = (2.75 × 10^-11)(150) = 4.1 × 10^-9 g

Problem 4: Finding Chloride Ion Concentration

Find [Cl^-]:
moles Ag⁺ = M × V
moles Ag⁺ = (0.04220)(0.100) = 0.00422 mol

Ratio 1:1 → moles Cl^- = 0.00422 mol

[Cl^-] = moles / volume
[Cl^-] = 0.00422 / 0.02500 = 0.169 M

Solubility Equilibrium Multiple Choice Questions

• 1A: In a solubility equilibrium, the...
• 2C: Which of the following could be used to express solubility?
• 3B: The equation that describes the solubility equilibrium of Ca₃(PO₄)₂ is...
• 4C: Which of the following will dissolve in water to produce a molecular solution?
• 5B: What is the concentration of barium ions in a 1.00 L solution containing 2.09 g of BaCl₂?
• 6C: What is the formula equation for the reaction that occurs when equal volumes of 0.20 M K₃PO₄ and 0.20 M ZnCl₂ are mixed together?
• 7C: Which of the following will not produce a precipitate when equal volumes of 0.20 M solutions are combined?
• 8A: When 1.0 × 10^-3 moles of CuCl₂(s) are added to 1.0 L of 1.0 × 10^-3 M IO₃^-, the...
• 9B: A solution contains both Ag⁺ and Mg²⁺ ions. During selective precipitation, these ions are removed one at a time by adding...
• 10D: Which of the following compounds has the lowest solubility?
• 11D: A saturated solution of NaCl contains 36.5 g of solute in 0.100 L of solution. The solubility of the compound is: A. 0.062 M
• 12A: The K_sp expression for a saturated solution of Ni₃(PO₄)₂ is...
• 13C: The solubility of CaF₂ is 3.3 × 10^-4 M. Determine the K_sp value of CaF₂.
• 14C: What is the solubility of SrF₂?
• 15C: [Question content missing]
• 16D: [Question content missing]
• 17D: [Question content missing]