Question

The solubility of aluminium sulphate is $1.0\times {10}^{-4}mol/lit$, the solubility product is :

• A. $108\times {10}^{-4}mol/lit$
• B. $10800\times {10}^{-20}mol/lit$
• C. $1080\times {10}^{-18}mol/lit$
• D. $1.08\times {10}^{-18}mol/lit$

Answer 1

The correct option is D $1.08\times {10}^{-18}mol/lit$

$A{l}_2(S{O}_4{)}_3\leftrightharpoons 2A{l}^{3+}+3S{O}_4^{2-}$
$K_{sp}=\left(2S{)}^2\right(3S{)}^3=108\times S^5$

$K_{sp}=1.08\times {10}^{-18}mol/lit$

Option D is correct.