A decomposition reaction has following mechanism: 2N2O5⟶4NO2+O2 (overal) N2O5⇌NO2+NO3 (fast decomposition) NO2+NO3⟶NO+NO2+O2 (slow) NO+NO3⟶2NO2 (fast) Determine rate law and show the mechanism corresponds to first order reaction.
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Solution
The rate will be determined from the slowest step i.e, RDS step, hence
Rate=K[NO2][NO3](1)
From the fast decomposition reaction we can write
Keq=[NO2][NO3][N2O5](2)
From (1) & (2) we get
Rate=KKeq[N2O5]
Hence mechanism corresponds to first order reaction.