For ten points, name this mechanism which Hughes and Ingold used to explain dehydrohalogenation.
The lack of hydrogen exchange plus the existence of a large element effect show that this occurs instead of carbanions. Proposed by E.D. Hughes and Sir Christopher Ingold, more evidence for it includes a large hydrogen isotope effect, the fact that it is unaccompanied by rearrangements, and that it follows second order kinetics. For ten points, name this mechanism which Hughes and Ingold used to explain dehydrohalogenation.
The lack of hydrogen exchange plus the existence of a large element effect show that this occurs instead of carbanions.
E2 or bimolecular elimination