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An external current source giving a current of `5.0A` was joined with Daniel cell arrangement opposing the normal current flow and was removed after 10 hrs. Before passing the current the LHE and RHE contained 1L each of `1M Zn^(2+)` and `Cu^(2+)` respectively. Find the EMF supplied by the Daniel cell after removal of teh external curretn source, `E^(@)` of `Zn^(2+)//Zn` and `Cu^(2+)//Cu` at `25^(@)C` is `-0.76` and `+0.34V` respectively. |
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Answer» Correct Answer - `1.143V` `n_(E) = (5 xx 3600 xx 10)/(96500)` `n_(E) = 1.865` `Zn^(2+) rarr ZN +2e^(-)` mole of `Zn^(2+)` deposited `= 0.932` mole of `Zn^(2+)` left `= 1 - 0.932` `=0.0673` `Cu rarr Cu^(2+) +2e^(-)` mole of `Cu^(2+)` produced `=0.932` so total mole of `Cu^(2+) = 1.932` `E_(cell) = E^(@) -(0.059)/(2)log.(0.0673)/(1.932)` `E_(cell) = 1.143V` |
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