Above 225 degrees Celsius, NO2 + CO giving NO + CO2 follows rate = k[NO2][CO]. With what kind of mechanism is this consistent?
AA two step path whose slow step uses two NO2
BA single step bimolecular collision of NO2 with CO
CA termolecular crash of two NO2 with one CO
DA chain mechanism carried by NO3 intermediates
Answer & Solution
Correct answer: B. A single step bimolecular collision of NO2 with CO
1. First order in each reactant is exactly the rate law an elementary bimolecular collision of NO2 with CO would give.
2. So the high temperature data are consistent with a single step mechanism.
3. Below 225 degrees Celsius the observed law changes to k[NO2]^2, pointing instead to a two step path with a slow NO2 plus NO2 step.
4. The two NO2 option therefore belongs to the low temperature regime, not this one.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 12 "Kinetics", section 12.6 Reaction Mechanisms_
Related questions
What forms when a substrate binds at an enzyme's active site during catalysis?Which enzyme model pictures the active site as flexible, changing shape to bind its substrWhich metal catalyses the hydrogenation of polyunsaturated fats and oils into saturated onHeterogeneous catalysis proceeds through at least four steps. Which comes first?Nitric oxide reacting with chlorine, 2NO + Cl2 giving 2NOCl, appears to occur as an elemenA reaction diagram shows a forward activation energy Ea and an enthalpy change delta H. WhIn the Arrhenius equation k = Ae^(-Ea/RT), what does the exponential factor represent?When carbon monoxide collides with an oxygen molecule, which collision orientation is more