InterviewSolution
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InterviewSolution
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The `E^(@)` values for the changes given below are measured againest `NHE` at `27^(@)C`. `Cu^(2+) + e rarr Cu^(+), E^(@) = + 0.15 V`, `Cu^(+) + e rarr Cu, E^(@) = + 0.50 V`, `Zn^(2+) + 2e rarr Zn, E^(@) = - 0.76 V` The temperature coefficient of emf a cell designed as `Zn"|"underset(1 M)(Zn^(2+))"||"underset(0.1 M)(Cu^(2+))"|"Cu` is `-1.4 xx 10^(-4)V` per degree. For a cell reaction in equilibrium `DeltaG = 0` and `DeltaG^(@) = -2.303 RTlog_(10)K_(c)`. The heat of reaction and entropy change during the reaction are are related by `DeltaG = DeltaH - TDeltaS`. The heat of reaction for the change `Zn+underset(0.1 M)(Cu^(2+)) hArr underset(1M)(Zn^(2+))+Cu` at `27^(@)C` is :A. `2.037 xx 10^(5)J`B. `2.116 xx 10^(5)J`C. `2.037 xx 10^(6)J`D. `2.116 xx 10^(6)J` |
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Answer» Correct Answer - A `E_(cell) = E_(cell)^(@) + (0.059)/(2)"log"([Cu^(2+)])/([Zn^(2+)])` `= 1.085 + (0.059)/(2)"log"(0.1)/(1) = 1.0555 V` `:. -DeltaG^(@) = n xx E xx F = 2 xx 1.055 xx 96500` `= 2.037 xx 10^(5)J` |
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