One possible mechanism would be the collision
of two N0 molecules to form the unstable but perfectly legitimate N202
molecule, followed either by its decomposition to N0 again or its collision
with 02 to form N02:
This mechanism is shown in fig 5 opposite.
If we assume that the buildup and breakdown of N202
are very fast reactions in comparison with the collision of N202
and 02, and that the first two reactions are
in equilibrium,
then we can describe the association and dissociation reactions involving
constants k1 and k2
in terms of an equilibrium
constant:
The slower collision of N202
with 02 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 N202
and 02, then the rate of production of
N02 will be proportional to the concentrations
of these two molecules:
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