Question

The pH of a saturated solution of a metal hydroxide of formula X(OH)\textsubscript{2 is 12.0 at 298 K. What is the solubility product of the metal hydroxide at 298 K (in mol\textsuperscript{3} L\textsuperscript{--3})?}

• A. $2 \times 10^{-6}$
• B. $1 \times 10^{-7}$
• C. $5 \times 10^{-5}$
• D. $2 \times 10^{-5}$
• E. $5 \times 10^{-7}$

Hint:

For a salt of type $AB_2$, $K_{sp}$ in terms of molar solubility ($s$) is $4s^3$. Here, $s$ is equal to the concentration of $X^{2+}$, which we found to be $5 \times 10^{-3}$.

Answer 1

Answer: (E)