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Question #44738
The Question
An aqueous solution of , buffered at , is electrolyzed at using smooth Platinum electrodes. A constant current of is passed for .
Given standard reduction potentials at :
Kinetic overpotentials () on Pt under these conditions:
Assume and . All gases are at .
Calculate the total minimum electrical energy required to drive the cell and produce the major anodic product. (Assume 100% current efficiency).
Options
- A.
17.66 kJ
- B.
18.14 kJ
- C.
11.87 kJ
- D.
13.61 kJ
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Mechanism_Trap
Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.
Concepts Behind This Question
Gibbs Energy and Spontaneity|Faraday's First and Second Laws|Electrolysis Product Prediction
Why This Question Is Tricky
Common Mistakes
This problem tests the critical intersection of Thermodynamics (Nernst Equation) and Kinetics (Overpotential) in electrolysis.
Students often calculate standard cell potentials, expecting spontaneity based purely on .
Here, thermodynamically, evolution is favored by at .
However, the 'Hidden Variable' is the kinetic overpotential on the Platinum electrode.
The high activation energy for formation shifts its discharge potential, making the major product.
Failing to account for this kinetic reality leads to incorrect product prediction and energy calculation.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Electrochemistry - Class 12 |
| Concept | Gibbs Energy and Spontaneity |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |