Question

The solubility of $A_2{X}_3$ is $y$ mol dm${}^{-3}$. Its solubility product is:

• A. $6y^4$
• B. $64y^4$
• C. $36y^5$
• D. $108y^5$

Answer 1

The correct option is D $108y^5$

For the salt $A_2{X}_3$, the relationship between solubility and solubility product is,

$K_{sp}=\left[A^{3+}{]}^2\right[X^{2+}{]}^3=\left(2s{)}^2\right(3s{)}^3=108s^5$

Substitute $s=y$ mol dm${}^{-3}$ in the above expression.

$K_{sp}=108y^5$.