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From the experimental data below for the reaction A + B → products, identify the rate law that fits the observations.
Exp. 1: [A] = 0.012, [B] = 0.035, initial rate = 0.1
Exp. 2: [A] = 0.024, [B] = 0.070, initial rate = 0.8
Exp. 3: [A] = 0.024, [B] = 0.035, initial rate = 0.1
Exp. 4: [A] = 0.012, [B] = 0.070, initial rate = 0.8
- rate = k [B]³
- rate = k [B]⁴
- rate = k [A][B]³
- rate = k [A]²[B]²
Correct answer: rate = k [B]³
Solution
The correct option is supported by the data showing that when the concentration of B is increased while A remains constant, the rate increases significantly, indicating a higher order dependence on B. Specifically, the rate increases by a factor of 8 when [B] is doubled, suggesting a cubic relationship with respect to [B].
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