A chemist investigates the gas-phase reaction summarized below.
Overall reaction: NO2(g) + CO(g) → NO(g) + CO2(g)
A proposed two-step mechanism is:
Step 1 (slow): NO2(g) + CO(g) → NO(g) + CO2(g)
Step 2 (fast): NO(g) + NO2(g) ⇌ N2O3(g)
Initial-rate experiments are carried out at 600 K using the mechanism above as a working model.
(a) Derive the rate law based on the mechanism.
(b) Predict and explain the qualitative effect on the initial rate when [NO2] is tripled and [CO] is unchanged.
(c) Predict and explain the qualitative effect on the initial rate when [CO] is halved and [NO2] is unchanged.
(d) Predict the numerical factor by which the initial rate changes when both [NO2] and [CO] are doubled. Justify your answer.