JEE Main & Advanced Chemistry Electrochemistry / विद्युत् रसायन Question Bank Electrode potential Ecell Nernst equation and ECS

  • question_answer
    The emf of a Daniel cell at 298K is \[{{E}_{1}}\]  \[Zn|\underset{(0.01\,\,M)}{\mathop{ZnS{{O}_{4}}}}\,||\underset{(1.0\,\,M)}{\mathop{CuS{{O}_{4}}}}\,|Cu\] when the concentration of \[ZnS{{O}_{4}}\] is 1.0 M and that of \[CuS{{O}_{4}}\] is 0.01 M, the emf changed to \[{{E}_{2}}\]. What is the relationship between \[{{E}_{1}}\] and \[{{E}_{2}}\]     [CBSE PMT 2003]

    A)                 \[{{E}_{2}}=0\ne {{E}_{1}}\]        

    B)                 \[{{E}_{1}}>{{E}_{2}}\]

    C)                 \[{{E}_{1}}<{{E}_{2}}\]  

    D)                 \[{{E}_{1}}={{E}_{2}}\]

    Correct Answer: B

    Solution :

               \[{{E}_{1}}={{E}_{o}}-\frac{0.0591}{2}\log \frac{0.01}{1}={{E}_{o}}+\frac{0.0591}{2}\times 2\]            \[{{E}_{2}}={{E}_{o}}-\frac{0.0591}{2}\log \frac{100}{0.01}={{E}_{o}}-\frac{0.0591}{2}\times 4\]                    \[\therefore \,\,{{E}_{1}}>{{E}_{2}}\].


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