Consider the following representation of a reaction mechanism.
step 1: unimolecular (fast)
step 2: bimolecular (slow)
step 3: unimolecular (fast)
which conclusion about the rate law for the reaction above is reasonable?
a. it is first order overall because step 1 is unimolecular.
b. it is first order overall because both steps 1 and 3 are unimolecular.
c. it is second order overall because step 2 is bimolecular.