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Question #44137
The Question
An aqueous solution of cold is electrolyzed at using inert electrodes. During the process, a total of of gas (measured at STP, where ) is collected from both electrodes combined. The current efficiency for the formation of peroxydisulfate () at the anode is , with the remaining anodic current resulting in the evolution of gas. The cathodic current efficiency for evolution is . The entire anodic solution is subsequently subjected to complete hydrolysis. What is the mass of produced?
Options
- A.
13.6 g
- B.
18.7 g
- C.
27.2 g
- D.
0.0 g
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
Peroxy Linkage Identification|Electrolysis Product Prediction|Half-Reaction Media Sensitivity
Why This Question Is Tricky
Common Mistakes
This problem tests the 'Media Sensitivity' and 'Kinetic Overpotential' exceptions in electrolysis.
Students often blindly apply standard reduction potentials (Nernst predictions) and assume 100% oxygen evolution at the anode (Option D), ignoring that cold, concentrated sulfuric acid on a platinum electrode kinetically favors the oxidation of sulfate to peroxydisulfate.
The trap is further layered by requiring the student to account for simultaneous gas evolution at both electrodes to correctly determine the total passed charge, and finally applying the correct stoichiometry for the sequential hydrolysis of the peroxy linkage.
Option B traps students who assume 100% current efficiency for peroxydisulfate, ignoring the competing oxygen evolution.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Redox Reactions - Class 11 Part 2 |
| Concept | Peroxy Linkage Identification |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |