Question

Determine $K_{sp}$ of the salt, if a saturated solution of $BaS{O}_4$ at ${25}^o$C contains $3.9\times {10}^{-5}$ mole$/$ liter of $B{a}^{2+}$ ions.

• A. $3.9\times {10}^{-5}$
• B. $3.9\times {10}^{-6}$
• C. $2.1\times {10}^{-7}$
• D. $1.5\times {10}^{-8}$
• E. $1.5\times {10}^{-9}$

Answer 1

The correct option is E $1.5\times {10}^{-9}$

Let S mol/L be the solubility of salt.
$S=\left[BaS{O}_4\right]=\left[B{a}^{2+}\right]=\left[S{O}_4^{2-}\right]=3.9\times {10}^{-5}mol/L$
$K_{sp}=\left[B{a}^{2+}\right]\left[S{O}_4^{2-}\right]=S\times S=3.9\times {10}^{-5}\times 3.9\times {10}^{-5}=1.5\times {10}^{-9}$