Second Order Half-life
Mediumchemistry
Half-life for second-order (A → products) with rate = k[A]² is:
Select the correct option:
Solution
Incorrect! Answer:
t1/2 = 1/(k[A]0)
- Integrated Rate Law (Second Order): [A]1−[A]01=kt.
- Substitute Half-life: At t=t1/2,[A]=2[A]0.
- Calculation:
- [A]02−[A]01=kt1/2
- [A]01=kt1/2
- Result: t1/2=k[A]01.
- Key Observation: For second-order reactions, the half-life is inversely proportional to the initial concentration.
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About This Question
- Subject
- chemistry
- Chapter
- chemical kinetics
- Topic
- second order half-life
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
t1/2 = 1/(k[A]0)
- Integrated Rate Law (Second Order): [A]1−[A]01=kt.
- Substitute Half-life: At t=t1/2,[A]=2[A]0.
- Calculation:
- [A]02−[A]01=kt1/2
- [A]01=kt1/2
- Result: t1/2=k[A]01.
- Key Observation: For second-order reactions, the half-life is inversely proportional to the initial concentration.
This medium difficulty chemistry question is from the chapter chemical kinetics, covering the topic of second order half-life. It appeared in the 2025 exam.
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