Question

For which of the following sparingly soluble salt, the solubility (s) and solubility product $ ({{K}_{sp}}) $ are related by the expression $ s={{({{K}_{sp}}/4)}^{1/3}} $ ?

• A. $ BaS{{O}_{4}} $
• B. $ C{{a}_{3}}{{(P{{O}_{4}})}_{2}} $
• C. $ H{{g}_{2}}C{{l}_{2}} $
• D. $ A{{g}_{3}}P{{O}_{4}} $
• E. $ CuS $

Answer 1

Answer: (C)

$ H{{g}_{2}}C{{l}_{2}} \rightleftharpoons \underset{s}{\mathop{Hg_{2}^{2+}}}\,+\underset{2s}{\mathop{2C{{l}^{-}}}}\, $
$ {{K}_{sp}}=[Hg_{2}^{2+}]{{[C{{l}^{-}}]}^{2}} $
$ =(s){{(2s)}^{2}} $
$ {{K}_{sp}}=4{{s}^{3}} $
$ s={{\left( \frac{{{K}_{sp}}}{4} \right)}^{1/3}} $