JEE Main & Advanced JEE Main Paper (Held on 12-4-2019 Afternoon)

  • question_answer
    The molar solubility of \[Cd{{(OH)}_{2}}\] is \[1.84\times {{10}^{-5}}M\] in water. The expected solubility of \[Cd{{(OH)}_{2}}\] in a buffer solution of pH = 12 is:             [JEE Main 12-4-2019 Afternoon]

    A) \[6.23\times {{10}^{-11}}M\]         

    B) \[1.84\times {{10}^{-9}}M\]

    C) \[\frac{2.49}{1.84}\times {{10}^{-9}}M\] 

    D) \[2.49\times {{10}^{-10}}M\]

    Correct Answer: D

    Solution :

    \[{{K}_{sp}}=4{{(s)}^{3}}\]           \[=4\times {{(1.84\times {{10}^{-5}})}^{3}}\]           \[Cd{{(OH)}_{2}}\rightleftharpoons C{{d}^{+2}}+2O{{H}^{-}}\]           \[S'\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,S'\,\,\,\,\,\,\,({{10}^{-2}}+S')\simeq {{10}^{-2}}\]           \[S'\times {{({{10}^{-2}})}^{2}}=4\times {{(1.84\times {{10}^{-5}})}^{3}}\]           \[S'=4\times {{(1.84)}^{3}}\times {{10}^{-11}}\]           \[(S')=2.491\times {{10}^{-10}}M\]


You need to login to perform this action.
You will be redirected in 3 sec spinner