Question

The removal of an ion is sometimes considered to be complete when its concentration drops to 1.00×10-6 m. What concentration of hydroxide would cause y2 to "completely" precipitate from a solution?

Answer 1

To find the hydroxide ion concentration that leads to 'complete' precipitation of ion y2, we need the Ksp value for the precipitate. With the Ksp and the given concentration of y2, we can calculate the hydroxide ion concentration necessary for precipitation.

Step-by-step explanation:

To determine the concentration of hydroxide ions (OH-) that would cause an unnamed ion, referred to as 'y2', to 'completely' precipitate from a solution at a concentration of 1.00×10-6 M, we need additional information such as the solubility product constant (Ksp) of the resulting precipitate. Assuming we have that constant, we could use it to calculate the hydroxide ion concentration needed for precipitation.

For instance, if the Ksp were known for the compound y(OH)2, and precipitation is deemed 'complete' at a y2+ concentration of 1.00×10-6 M, the equation representing the dissociation of y(OH)2 would be: y(OH)2 → y2+ + 2OH-. The Ksp expression would be Ksp = [y2+][OH-]2. We could then solve for [OH-] when [y2+] is 1.00×10-6M.