The proposed mechanism for the reaction 2A + B -> D + E is: Step I: A + B -> C + D (slow) Step II: A + C -> E (fast) Write the rate law for the overall reaction.

r = k[A]²[B]
r = k[A][B]
r = k[A]²
r = k[A][C]

Correct answer: r = k[A][B]

Solution

The slow step (rate-determining step) is A + B -> C + D, which is bimolecular in A and B, so the rate law is r = k[A][B].

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