A solution is prepared by mixing 50.0 mL of 0.50 M Cu(NO₃)₂ with 50.0 mL of 0.50 M Co(NO₃)₂. Sodium hydroxide is added to the mixture. Which hydroxide precipitates first and what concentration of hydroxide ions present in solution will accomplish the separation? K_sp = 2.2 *10¯²⁰ for Cu(OH)₂, K_sp = 1.3 *10¯¹⁵ for Co(OH)₂ A) Co(OH)₂; [OH¯] = 6.9 * 10¯⁶ M B) Co(OH)₂; [OH¯] = 2.6 * 10¯⁷ M C) Cu(OH)₂; [OH¯] = 1.8 * 10¯⁷ M D) Cu(OH)₂; [OH¯] = 1.1 * 10¯⁹ M E) Cu(OH)₂; [OH¯] = 1.0 * 10¯¹⁷ M

Question

Quizplus · Accepted Answer

Cu(OH)₂ will precipitate first because it has a lower Ksp value, indicating it is less soluble. The concentration of OH⁻ required for Cu(OH)₂ to precipitate is calculated using the Ksp expression: [OH⁻] = √(Ksp / [Cu²⁺]) = √(2.2 * 10⁻²⁰ / 0.25) = 1.1 * 10⁻⁹ M.

A Solution Is Prepared by Mixing 50