A large number of both homogeneous and heterogeneous reactions do not follow simple rate laws. Examples of reactions that don’t follow simple elementary rate laws are discussed below.
The overall order of a reaction does not have to be an integer, nor does the order have to be an integer with respect to any individual component. As an example, consider the gas-phase synthesis of phosgene,
CO + CL2 → COCL2
in which the kinetic rate law is
This reaction is first order with respect to carbon monoxide, three-halves order with respect to chlorine, and five-halves order overall.
Sometimes reactions ...