WB JEE Medical WB JEE Medical Solved Paper-2007

  • question_answer
    In    the     electrochemical     reaction, \[2F{{e}^{3+}}+Zn\xrightarrow{{}}Z{{n}^{2+}}+2F{{e}^{2+}}\] increasing the concentration of\[F{{e}^{2+}}\]

    A)  increases cell emf

    B)  increases the current flow

    C)  decrease the cell emf

    D)  alter the pH of the solution

    Correct Answer: C

    Solution :

                     \[2F{{e}^{3+}}+zn\to Z{{n}^{2+}}+2F{{e}^{2+}}\] \[2F{{e}^{3+}}+2{{e}^{-}}\to 2F{{e}^{2+}}\] According Nemsts equation, \[{{E}_{cell}}=E_{cell}^{o}-\frac{RT}{nF}\ln \frac{{{[F{{e}^{2+}}]}^{2}}}{{{[F{{e}^{3+}}]}^{2}}}\] \[{{\text{E}}_{\text{cell}}}\]is depend on concentration of \[\text{F}{{\text{e}}^{2+}}.\] Therefore, \[[F{{e}^{2+}}]\]decrease \[{{E}_{cell}}.\]


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