Definition of Molecularity of a reaction? [closed]








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If nucleophilic attack occurs simultaneously at two seperate electrophilic sites of the molecule following SN2 at each site, will the moleculularity still be 2? Does molecularity depend on the total number of reacting entities, or the number of reacting entities at a particular site?


I think molecularity will be defined wrt a specific site, in a molecule.


Please elaborate.




If the reaction requires simultaneous nucleophilic attack of both sites to proceed through an elementary reaction step, then we would describe that step as having molecularity of three.


If it just so happened that a particular molecule in a reaction had two simultaneous nucleophilic attacks at different reaction sites that could each have proceeded at different times, then the two would be considered different elementary steps each with molecularity of two.


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