A) \[2.8\times {{10}^{-4}}\]
B) \[2.8\times {{10}^{-3}}\]
C) \[2.8\times {{10}^{-2}}\]
D) \[2.8\times {{10}^{-5}}\]
Correct Answer: A
Solution :
[a] \[\underset{0}{\mathop{\underset{100\times 0.1}{\mathop{MgC{{l}_{2}}}}\,}}\,\,\,\,\,\,+\,\,\,\,\,\underset{0}{\mathop{\underset{100\times 0.2}{\mathop{2NaOH}}\,}}\,\to \underset{10}{\mathop{\underset{0}{\mathop{Mg}}\,}}\,\underset{20}{\mathop{\underset{0}{\mathop{{{(OH)}_{2}}}}\,}}\,\,\,\,\,+\,\,\,\,\underset{After\,mixing}{\mathop{\underset{Initial\,moles}{\mathop{2NaCl}}\,}}\,\] \[\therefore {{K}_{sp}}=\left[ \frac{10}{200} \right]{{\left[ \frac{20}{200} \right]}^{2}}=5\times {{10}^{-4}}\] But actually \[{{K}_{sp}}\] of \[Mg{{\left( OH \right)}_{2}}=1.2\times {{10}^{-11}}\] \[\therefore \text{ }4{{S}^{3}}=1.2\times {{10}^{-11}}\] Find S then \[\left[ O{{H}^{-}} \right]=2S\] which is \[2.8\times {{10}^{-4}}.\]
You need to login to perform this action.
You will be redirected in
3 sec
