InterviewSolution
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InterviewSolution
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The standard reduction potential for `Zn^(2+)//Zn, Ni^(2+)//Ni` and `Fe^(2+)//Fe` are `-0.76, -0.23` and `0.44V` respectively. The reaction `X + Y^(2) rarr X^(2+) + Y` will be spontaneous when:A. `X = Ni, Y = Zn`B. `X = Fe, Y = Zn`C. `X = Zn, Y = Ni`D. `X = Ni, Y = Fe` |
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Answer» Correct Answer - C The elements with high negative value of standard reduction potential are good reducing agent and can be easily oxidised. ltbRgt Thus `X` should have high negative value of standard potential then `Y`, so that it will be oxidised to `X^(2+)` by reducing `Y^(2+)` to `Y`. `X = Zn, Y = Ni` `Zn + Ni^(2+) rarr Zn^(2+) + Ni` Alternatively, for a spontaneous reaction `E^(@)` must be positive. `E^(@) = E_("reduced")^(@) - E_("oxidised")^(@)` `= -0.23 - (0.76)` implies `E^(@) = +0.53 V` |
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