Question

Calculate the solubility product of calcium hydroxide if the solubility of Ca(OH)2(s) in water at 25◦C is 0.011 M.

Choices:
1. 1.1 × 10−5
2. 5.3 × 10−6
3. 2.7 × 10−6
4. 1.5 × 10−8
5. 1.2 × 10−4

Answer 1

Ca(OH)2 ==> Ca^2+ + 2OH^-
Ksp = (Ca^2+)(OH^=)^2
Set up an ICE chart, substitute into the Ksp expression and solve for Ksp.
The problem tells you that the solubility of Ca(OH)2 is 0.011M, therefore, (Ca^2+) must be 0.011M and (OH^-) must be twice that. Plug and chug.

Answer 2

is the answer 2)5.3....

Answer 3

The answer is (2) but that is 5.3E-6 and not just 5.3.

Answer 4

5.1×10^-6