Determining an Intermediate

[Nicole Gamboa 2M]

Hi All,
In the elementary steps of a reaction mechanism, I understand that the reaction intermediate is the item that is cancelled out between the reactions, however I don't understand how the reaction intermediate is chosen. Does the intermediate have to be given in the reaction or is there a way to determine what it should be without it being given?
Thanks!

[Nick_OConnell_2F]

Hi Nicole,

The intermediate of a reaction is any compound that is not present in either the reactants or products of the given reaction. For example in the reaction NO2 + CO -> NO + CO2 from the course reader (pg 69), you see that NO3 is a product of elementary step 1. However, NO3 is not a reactant or a product in the aforementioned original equation. Thus, you know it is the intermediate. Hope this helps.