Question

The solubility of $BaSO _{4}$ in water is $2.42 \times 10^{-3}\, gL ^{-1}$ at $298 \,K$. The value of its solubility product $\left( K _{ sp }\right)$ will be
(Given molar mass of $BaSO _{4}=233 \,g\, mol ^{-1}$ )

• A. $1.08 \times 10^{-8} \, mol^{2} \, L^{-2}$
• B. $1.08 \times 10^{-10} \, mol^{2} \, L^{-2}$
• C. $1.08 \times 10^{-14} \, mol^{2} \, L^{-2}$
• D. $1.08 \times 10^{-12} \, mol^{2} \, L^{-2}$

Answer 1

Answer: (B)

Sol. Solubility of $BaSO _{4}, s =\frac{2.42 \times 10^{-3}}{233}\left( mol\, L ^{-1}\right)$

$=1.04 \times 10^{-5}\left( mol \,L ^{-1}\right)$

$BaSO _{4}( s ) \rightleftharpoons \underset{s}{{ Ba }^{2+}}( aq )+ \underset{s}{SO _{ 4 }^{2-}}( aq )$

$K _{ sp }=\left[ Ba ^{2+}\right]\left[ SO _{4}^{2-}\right]= s ^{2}$

$=\left(1.04 \times 10^{-5}\right)^{2}$

$=1.08 \times 10^{-10} \,mol ^{2}\,L ^{-2}$