Question

Zirconium phosphate $[Zr_3(PO_4)_4]$ dissociates into three zirconium cations of charge +4 and four phosphate anions of charge — 3. If molar solubility of zirconium phosphate is denoted by S and its solubility product by $K_ {sp}$ then which of the following relationship between S and $K_{sp}$ is correct ?

• A. $S =\left\{K_{sp}/ \left(6912\right)^{1/7}\right\}$
• B. $S=\left\{K_{sp}/144\right\}^{1/7}$
• C. $S = \left\{K_{sp}/6912\right\}^{1/7}$
• D. $S = \left\{K_{sp}/6912\right\}^{7}$

Answer 1

Answer: (C)

$Zr_3(PO_4)_4 \to \underset{3s}{3Zr^{+3}}+\underset{4s}{4\,PO^{-3}_{4}}$

$Ksp =(3 s )^{3}(4 s )^{4}$

$s =\left(\frac{ ksp }{6912}\right)^{1 / 7}$