A saturated solution of calcium hydroxide, Ca(OH)₂, is in contact with excess solid Ca(OH)₂. Which of the following statements correctly describes what will happen when aqueous HCl (a strong acid) is added to this mixture, and system returns to equilibrium? (For Ca(OH)₂, K_sp = 6.5 × 10⁻⁶) A)The solubility of Ca(OH)₂ will be unchanged. B)The OH ⁻ concentration will decrease and the Ca ²⁺ concentration will increase. C)The OH ⁻ concentration will increase and the Ca ²⁺ concentration will decrease. D)The concentrations of both Ca ²⁺ and OH ⁻ will increase. E)The solubility of Ca(OH)₂ will decrease.

Question

Quizplus · Accepted Answer

When HCl is added to the saturated solution of Ca(OH)₂, it will react with the OH ⁻ ions to form water, according to the equation: HCl + OH ⁻ → H2O + Cl ⁻ This will decrease the concentration of OH ⁻ ions in solution, shifting the equilibrium to the right according to Le Chatelier's principle to replace the lost OH ⁻ ions. Therefore, the Ca ²⁺ concentration will increase as more solid Ca(OH)₂ dissolves to form more Ca ²⁺ ions. The decrease in OH ⁻ concentration will also cause a decrease in the solubility product (Ksp) of Ca(OH)₂, as Ksp = [Ca ²⁺][OH ⁻]. Therefore, the solubility of Ca(OH)₂ will also decrease.

A Saturated Solution of Calcium Hydroxide, Ca(OH)2, Is in Contact

A Saturated Solution of Calcium Hydroxide, Ca(OH)₂, Is in Contact