RAJASTHAN ­ PET Rajasthan PET Solved Paper-2012

  • question_answer
    The standard emf of the cell \[Zn+C{{u}^{2+}}\xrightarrow[{}]{{}}Cu+Z{{n}^{2+}}\]is 1.10 at\[25{}^\circ C\]. The emf of the cell when\[0.1\text{ }M\,C{{u}^{2+}}\]and\[0.1\text{ }M\,Z{{n}^{2+}}\]solution are used will be

    A)  1.10V

    B)  \[+\text{ }0.110\text{ }V\]

    C)  \[-1.10V\]

    D)  \[-0.11\,V\]

    Correct Answer: A

    Solution :

     \[Zn+C{{u}^{2+}}\xrightarrow[{}]{{}}Z{{n}^{2+}}+Cu\] \[\therefore \]Zn is anode and Cu is cathode \[{{E}_{cell}}=E_{cell}^{o}-\frac{0.591}{n}\log \left[ \frac{Z{{n}^{2+}}}{C{{u}^{2+}}} \right]\] Given,     \[E_{cell}^{o}=1.1V,n=2\] \[[Z{{n}^{2+}}]=0.1M,[C{{u}^{2+}}]=0.1M\] \[\therefore \] \[{{E}_{cell}}=1.1-\frac{0.592}{2}\log \left[ \frac{0.1}{0.1} \right]\] Or \[{{E}_{cell}}=1.10-0\] \[=1.10V\]


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