Calculate the molar solubility of Fe(OH)₂ in a solution with pH = 13.15.(K_sp Fe(OH)₂ = 1.6 x 10^-14)

Question

Quizplus · Accepted Answer

The solubility of Fe(OH)2 in basic solution can be expressed as follows:

Fe(OH)2(s) ⇄ Fe2+(aq) + 2OH-(aq)

The Ksp expression for this reaction is:

Ksp = [Fe2+][OH-]2

Since the pH of the solution is 13.15, we know that [OH-] = 10^-0.85 M.

Substituting into the Ksp expression:

1.6 x 10^-14 = [Fe2+](10^-0.85)^2

Solving for [Fe2+], we get:

[Fe2+] = 8.0 x 10^-13 M

Since Fe(OH)2 dissociates to form two Fe2+ ions, the molar solubility of Fe(OH)2 is:

s = [Fe2+] / 2 = 4.0 x 10^-13 M

Therefore, the best choice is D.

Calculate the Molar Solubility of Fe(OH)2 in a Solution with PH