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) Using only information from the mechanism, derive the rate law that is consistent with the rate-limiting step.
(b) Explain, without performing numerical calculations, how the initial rate would qualitatively change if the concentration of NO2 were tripled while the concentration of CO were kept constant.
(c) Explain how the initial rate would qualitatively change if the concentration of CO were halved while the concentration of NO2 remained unchanged.
(d) The chemist plans to double both reactant concentrations simultaneously by compression at constant temperature. Predict the factor by which the initial rate will change and justify your prediction.
(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.