8. A proposed mechanism for the decomposition of hydrogen peroxide (H2O2) consists of three elementary steps:

H2O2(g) → 2OH(g)
H2O2(g) + OH(g) → H2O(g) + HO2(g)
HO2(g) + OH(g) → H2O(g) + O2(g)

The rate law of the reaction is first order with respect to H2O2(g). Which step of the mechanism is the rate-determining step?

A. The first step.
B. The third step.
C. Reactions in the gas phase do not have rate determining steps.
D. Steps 1 and 2 are both rate detemining steps.
E. The second step.