One possible mechanism would be the collision
of two N0 molecules to form the unstable but perfectly legitimate N_{2}0_{2}
molecule, followed either by its decomposition to N0 again or its collision
with 0_{2} to form N0_{2}: This mechanism is shown in fig 5 opposite. If we assume that the buildup and breakdown of N_{2}0_{2} are very fast reactions in comparison with the collision of N_{2}0_{2} and 0_{2}, and that the first two reactions are in equilibrium, then we can describe the association and dissociation reactions involving constants k_{1} and k_{2} in terms of an equilibrium constant:
The slower collision of N_{2}0_{2} with 0_{2} is called the rate-determining step, since the overall reaction rate depends on how fast the slowest step occurs. If the reaction takes place by collision of N_{2}0_{2 }and 0_{2}, then the rate of production of N0_{2} will be proportional to the concentrations of these two molecules: |