Why interconversion in tautomers is so rapid? Looking at the examples in Tautomer on Wikipedia, it seems that the hydrogen needs to travel a significant distance (~20&Aring;) for the interconversion to take place. What lets it happen so fast? Why interconversion is preferred over maintaining its position?


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If you are using a protic solvent (the most common situation when you're dealing with polar functional groups), then you are "cheating" because the solvent can generate its own proton transfers, making the reaction look rapid.