Ozone is rapidly removed from polluted urban air by reaction with nitric oxide according to the overall stoichiometric equation
O3(g) + NO(g) → NO2(g) + O2(g)
The following two-step mechanism has been proposed.
Step 1 O3(g) + NO(g) ⇌ NO3(g) (fast equilibrium)
Step 2 NO3(g) + NO(g) → 2 NO2(g) (slow)
Answer the following questions about this mechanism.
(a) Identify the reaction intermediate in the proposed mechanism and justify your choice.
(b) Describe how the relative speeds of the two elementary steps influence which species appear in the experimentally observed rate law for the overall reaction.
(c) Predict qualitatively how the initial rate will change if the initial concentration of NO is doubled while the concentration of O3 is kept constant. Explain your reasoning without performing a detailed mathematical derivation.
(d) State whether the overall reaction is expected to be first, second, or higher order with respect to O3. Support your answer with reference to the elementary steps given.