https://doi.org/10.1351/goldbook.Z06751
This hypothesis states that, if in an acid catalysed reaction, \(\log _{10}k_{1}\) (first-order @O04322@ of the reaction) is linear in \(H_{0}\) (Hammett @A00081@), water is not involved in the @T06468@ of the @R05139@. However, if \(\log _{10}k_{1}\) is linear in \(\log _{10}\left[\text{H}^{+}\right]\) then water is involved. This has been shown to be incorrect by Hammett himself.