Question

Solubility of thorium phosphate (molar mass$=m$) is $wg/100$ mL at ${25}^{o}C$. The $K_{sp}$ of thorium phosphate is:

• A. $6.912\times {10}^{10}\times {\left(\frac{w}{m}\right)}^7$
• B. $6.912\times {10}^3\times {\left(\frac{w}{m}\right)}^7$
• C. $1.08\times {10}^7\times {\left(\frac{w}{m}\right)}^5$
• D. ${10}^2\times {\left(\frac{w}{m}\right)}^2$

Answer 1

Answer: (A)

$6.912\times {10}^{10}\times {\left(\frac{w}{m}\right)}^7$

${Th}_3{\left({PO}_4\right)}_4\rightleftharpoons 3\underset{3s}{{Th}^{4+}}+4\underset{4s}{{PO}_4^{3-}}$
$K_{sp}=3^3\cdot 4^4\cdot {\left(s\right)}^7=6912\times {\left(\frac{10w}{m}\right)}^7(s=\frac{10w}{m}mol/litre)$
$=6.912\times {10}^{10}\times {\left(\frac{w}{m}\right)}^7$