Law (at low [AZO])
![[Azomethane Mechanism (1a)]](../images/three1a.gif)
DECOMPOSITION OF AZOMETHANE
Review
| Overall Reaction | AZO → C2H6 + N2 |
| Experimental Rate Law (at low [AZO]) | +d[N2]/dt = ka[AZO]2 |
| Proposed Mechanism | |
If the reaction AZO → C2H6 + N2 was elementary, the rate law would be:
+d[N2]/dt = k[AZO]Since this is inconsistent with the experimentally determined rate law,
+d[N2]/dt = ka[AZO]2it can be stated that the reaction is not elementary.
Overall Reaction
Before deriving any rate expressions, the proposed mechanism should be checked to ensure that the sum of its reactions gives the overall reaction.
Note : When summing reversible reactions in a mechanism, only the net direction of the reversible reactions are used.
Summing the reactions in the proposed mechanism:
2AZO → AZO + AZO* AZO* → C2H6 + N2 2AZO + AZO* → AZO + AZO* + C2H6 + N2
On simplifying