Question

The generic metal hydroxide M(OH)2 has Ksp = 7.65×10−12. (NOTE: In this particular problem, because of the magnitude of the Ksp and the stoichiometry of the compound, the contribution of OH− from water can be ignored. However, this may not always be the case.) Part A What is the solubility of M(OH)2 in pure water? Express your answer with the appropriate units

Answer 1

Solubility will be = 1.24 X 10⁻⁴ M

Step-by-step explanation:

When the concentration of the salt dissolved in water is very low the concentration of hydroxide ions generated by the water can be ignored.

The dissociation of metal hydroxide can be expressed as:

`M(OH)_(2)--->M^(+2)+2OH^(-)`

Ksp =
`[M^(+2)][OH^(-)]^(2)`

Let the solubility of the metal hydroxide is "s"

Ksp = (s)(2s)²=4s³

Ksp = 7.65X10⁻¹² = 4s³

Therefore

s = 1.24 X 10⁻⁴ M