The solubility product for Zn1OH22 is 3.0 * 10-16. The formation constant for the hydroxo complex, Zn1OH242 - , is 4.6 * 1017. What concentration of OH- is required to dissolve 0.015 mol of Zn1OH22 in a liter of solution?

Verified step by step guidance

Identify the dissolution reaction for Zn(OH)_2: Zn(OH)_2 (s) \rightleftharpoons Zn^{2+} (aq) + 2OH^- (aq).

Write the expression for the solubility product (K_{sp}): K_{sp} = [Zn^{2+}][OH^-]^2.

Identify the formation reaction for the hydroxo complex: Zn^{2+} (aq) + 4OH^- (aq) \rightleftharpoons [Zn(OH)_4]^{2-} (aq).

Write the expression for the formation constant (K_f): K_f = \frac{[Zn(OH)_4^{2-}]}{[Zn^{2+}][OH^-]^4}.

Set up the equilibrium expressions and solve for [OH^-] using the given K_{sp} and K_f values, considering the total concentration of Zn(OH)_2 initially present.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Solubility Product (Ksp)

The solubility product constant (Ksp) is an equilibrium constant that applies to the solubility of sparingly soluble ionic compounds. It is defined as the product of the molar concentrations of the ions, each raised to the power of their coefficients in the balanced equation. For Zn(OH)2, Ksp = [Zn^2+][OH^-]^2, which helps determine the concentration of ions in a saturated solution.

Formation Constant (Kf)

The formation constant (Kf) quantifies the stability of a complex ion in solution. It is defined as the equilibrium constant for the formation of a complex from its constituent ions. In this case, Kf for Zn(OH)4^2- indicates how readily Zn^2+ ions react with OH- ions to form the hydroxo complex, influencing the solubility of Zn(OH)2 in the presence of hydroxide ions.

Equilibrium and Le Chatelier's Principle

Equilibrium in chemistry refers to the state where the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. Le Chatelier's Principle states that if a system at equilibrium is disturbed, it will shift in a direction that counteracts the disturbance. This principle is crucial for understanding how changes in OH- concentration affect the solubility of Zn(OH)2 and the formation of its hydroxo complex.

Recommended video:

Guided course

07:32

Le Chatelier's Principle

Related Practice

Textbook Question

The solubility product constants of PbSO4 and SrSO4 are 6.3 * 10-7 and 3.2 * 10-7, respectively. What are the values of 3SO4 2 - 4, 3Pb2 + 4, and 3Sr2 + 4 in a solution at equilibrium with both substances?

Textbook Question

The value of K_sp for Cd(OH)₂ is 2.5 × 10^-14. (a) What is the molar solubility of Cd(OH)₂?

Textbook Question

The value of K_sp for Cd(OH)₂ is 2.5 × 10^–14. (b) The solubility of Cd(OH)₂ can be increased through formation of the complex ion CdBr₄^2- (K_f = 5 × 10³). If solid Cd(OH)₂ is added to a NaBr solution, what is the initial concentration of NaBr needed to increase the molar solubility of Cd(OH)₂ to 1.0 × 10^-3 mol/L?

Textbook Question

(a) Write the net ionic equation for the reaction that occurs when a solution of hydrochloric acid (HCl) is mixed with a solution of sodium formate 1NaCHO22.