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Question #44079
The Question
A localized corrosion cell forms on a structural iron beam exposed to an aerated aqueous solution of at . The anodic process involves the oxidation of to , while the cathodic process is the reduction of to . Given the standard reduction potentials: and . The first hydrolysis constant () of is . Assume the partial pressure of is , the local concentration of is , and . Calculate the operating cell potential () of this corrosion cell. (Take at ).
Options
- A.
1.56 V
- B.
1.32 V
- C.
1.08 V
- D.
1.44 V
Check Your Answer
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
Ionic Product of Water (Kw)|Nernstian Redox Equilibrium|Stock Notation Logic|Corrosion as Electrochemical Process
Why This Question Is Tricky
Common Mistakes
This problem tests the integration of ionic equilibrium (salt hydrolysis) with Nernstian redox thermodynamics.
Students frequently fall into the trap of assuming standard conditions () or neutral water (pH = 7) for corrosion cells.
The hidden variable is the local concentration, which is drastically suppressed by the acidic hydrolysis of the ions.
Failing to couple and to the cathodic half-reaction leads to a massive stoichiometric error in the Nernst equation due to the 4th power dependence on .
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Equilibrium - Class 11 Part 1 |
| Concept | Ionic Product of Water (Kw) |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |