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Question #44845
The Question
A gaseous compound containing a radioactive isotope undergoes two simultaneous parallel first-order processes at : a chemical decomposition with a rate constant , and a nuclear -decay transforming the isotope in to form a new species with a decay constant . The chemical decomposition has a temperature coefficient (the rate triples for every rise). If the system is heated to and allowed to react until is completely exhausted, what is the mole fraction of in the final product mixture?
Options
- A.
0.10
- B.
0.50
- C.
0.14
- D.
0.90
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Exception_Exposure
Learn to identify edge cases and boundary exceptions that JEE examiners hide in math problems.
Concepts Behind This Question
Radioactive Decay as Kinetics|Temperature Coefficient (Q10)|Activation Energy Trap
Why This Question Is Tricky
Common Mistakes
This problem tests the fundamental distinction between chemical kinetics and nuclear kinetics.
Students often blindly apply the temperature coefficient ( rule) to all rate constants provided in a problem.
The 'Hidden Variable' here is the nature of the activation energy: chemical reactions have an activation barrier (), making them temperature-dependent, whereas radioactive decay is a stochastic nuclear process with no thermal activation barrier (), rendering its decay constant () invariant to temperature changes.
Failing to recognize this exception leads to the incorrect assumption that both rates increase equally, yielding a mole fraction of 0.50.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Chemical Kinetics - Class 12 |
| Concept | Radioactive Decay as Kinetics |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |