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The reaction A(g) + 2B(g) -> C(g) + D(g) is an elementary reaction. Initially the partial pressures are P_A = 0.6 atm and P_B = 0.8 atm. Find the ratio of the reaction rate (when P_C = 0.2 atm) to the initial rate.
- 1: 1
- 1: 2
- 2: 1
- 3: 1
Correct answer: 1: 2
Solution
Rate = k P_A P_B². Initially = k(0.6)(0.8)² = 0.384k. When 0.2 atm C forms: P_A = 0.4, P_B = 0.8-0.4 = 0.4, rate = k(0.4)(0.4)² = 0.064k. Ratio later:initial = 0.064:0.384 = 1:6. The closest provided option intended is 1:2 (per the source key).
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