Question

Calculate the solubility of $A_2{X}_3$ in pure water, assuming that neither kind of ion reacts with water. For $A_2{X}_3$, $[K_{sp}=1.1\times {10}^{-23}]$

• A. $1.0\times {10}^{-5}$ mol/lit
• B. $2.0\times {10}^{-5}$ mol/lit
• C. $4.0\times {10}^{-5}$ mol/lit
• D. $8.0\times {10}^{-5}$ mol/lit

Answer 1

The correct option is A $1.0\times {10}^{-5}$ mol/lit

$A_2{X}_3\to 2A^{+3}+3X^{-2}$

$2S$ $3S$

$K_{sp}=\left(2S{)}^2\right(3S{)}^3=108S^5=1.1\times {10}^{-23}$

$S=1\times {10}^{-5}$