How do you distinguish between E1 and E2 reactions?

1 Answer

The only way to distinguish between E1 and E2 reaction is to do an experiment.

Experiment with E1 and E2 reactions from jamesash.wpengine.netdna-cdn.com

An E1 mechanism follows first order kinetics. The rate determining step is the loss of the leaving group to form a carbocation. So its rate depends only on the concentration of the substrate.

An E2 mechanism follows second order kinetics. The elimination is a single-step process, in which the leaving group exits at the same time as the base attacks. So the rate depends on the concentrations of both the base and the substrate.