The solubility of a salt MX2 with a molar mass of 114 g/mole is 3.42 g/liter. Calculate the Ksp.

Question

Quizplus · Accepted Answer

Ksp = [M]^2[X]^4

From the given solubility, we can calculate the molarity of MX2:

Molarity = (3.42 g/L) / (114 g/mol) = 0.03 M

Since MX2 dissolves into M and 2X ions, we can represent the dissociation as:

MX2 ↔ M + 2X

At equilibrium, let's say x mol/L of MX2 dissociates, so the equilibrium concentrations of M and X ions are both 2x mol/L. Then, the solubility product expression would be:

Ksp = (2x)^2 (2x)^4 = 16x^6

But we know that 2x is equal to the molarity of MX2, which we calculated as 0.03 M. Substituting this value:

Ksp = (16 x 0.03^6) = 1.08 x 10^-4

Therefore, the answer is B.

The Solubility of a Salt MX2 with a Molar Mass