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Question #44773
The Question
A \ce{H2-O2} fuel cell operates using an aqueous \ce{KOH} electrolyte. Due to continuous operation and solvent evaporation, the boiling point of the electrolyte solution is elevated by . Assume the density of the dilute solution is (molarity molality). The standard reversible potential of the cell is . The cell operates at a constant current of and has a cell constant . The molar conductivity of the \ce{KOH} solution follows the Debye-Hückel-Onsager equation: . Given: , , . Assuming activation and concentration overpotentials are negligible, what is the operational voltage () of the fuel cell at this state?
Options
- A.
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- C.
- D.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Numerical_Precision
Improve calculation stamina and avoid rounding errors in high-stakes competitive examinations.
Concepts Behind This Question
Fuel Cell Efficiency|Molar Conductivity Trend|Boiling Point Elevation (Solvent vs Solution)
Why This Question Is Tricky
Common Mistakes
This problem tests the intersection of Colligative Properties, Conductance, and Fuel Cell Thermodynamics.
Students often treat fuel cell electrolytes as ideal, constant resistors.
The primary trap is forgetting the van 't Hoff factor () for the strong electrolyte \ce{KOH} during the boiling point elevation step.
If is mistakenly used, the calculated concentration doubles (), leading to an incorrect molar conductivity (), an incorrect internal resistance, and ultimately the distractor .
A secondary trap involves ignoring the Debye-Hückel-Onsager non-ideal behavior entirely and using , which leads to .
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Electrochemistry - Class 12 |
| Concept | Fuel Cell Efficiency |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |