Question

A saturated solution of limestone (calcium carbonate) is found to have a calcium ion concentration of 3.24 x 10-6 M. What is the Ksp of calcium carbonate?

a. 3.24 x 10-6 c. 1.05 x 10-11
b. 1.24 x 10-11 d. 6.48 x 10-6

Answer 1

c. 1.05 x 10-11

Step-by-step explanation:

The solubility product constant (Ksp) for calcium carbonate (CaCO3) can be calculated using the following equation:

CaCO3(s) ⇌ Ca2+(aq) + CO32-(aq)

Ksp = [Ca2+][CO32-]

We are given the concentration of calcium ions in the saturated solution of calcium carbonate as [Ca2+] = 3.24 x 10-6 M.

Since calcium carbonate is a sparingly soluble salt, we can assume that the concentration of CO32- is also 3.24 x 10-6 M, since they have a 1:1 stoichiometry in the balanced equation.

Therefore,

Ksp = [Ca2+][CO32-] = (3.24 x 10-6 M)(3.24 x 10-6 M) = 1.05 x 10-11