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Ethylene oxide decomposes by a first-order process: C2H4O(g) -> CH4(g) + CO(g). Starting from a pure sample at an initial pressure of 80 mm Hg, the total pressure becomes 120 mm Hg after 20 minutes. Determine the half-life of the reaction (in minutes).
- approx 19.9 min
- approx 24.2 min
- approx 13.9 min
- approx 27.7 min
Correct answer: approx 19.9 min
Solution
Total pressure rises because 1 mole of gas becomes 2 moles; the reactant partial pressure determines the first-order rate, giving a half-life near 19.9 min.
Related JEE Main Chemistry questions
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