We’re being asked to determine which ionic compound is not affected by the pH of the solution.
For the solubility of an ionic compound to be not affected by a change in pH, it must contain a neutral ion.
The acidic ions are usually cations and include:
1. Transition metals with a charge of +2 or higher. Transition metals not satisfying this condition are neutral.
2. Main group metals with a charge of +3 or higher. Main group metals not satisfying this condition are neutral.
3. Amines, which are compounds that contain only N and H (i.e. NH3) or C, N, and H (i.e. CH3NH2)
To determine if an anion is a basic ion, we should add H+ to it.
If the addition of H+ leads to:
1. a weak acid, the anion is basic.
2. a strong acid, the anion is neutral.
Consider the following table of Ksp values.
The molar solubility of __________ is not affected by the pH of the solution.