Analyzing the κT factor in solvent media shows that the tunneling is substantial and that its contribution decreases going from the gas phase to increasingly polar solvents for 1H,H and 5CF3,CF3, with the latter approaching a semiclassical value of ~ 1, indicating that the thermal reaction dominates due to lower barriers. In the case of 5Me,Me, however, there is no clear trend, with κT being higher in toluene than in the gas phase, and an intermediate value in THF. This may not be the case when the reaction is carried out in a real solvent, since the presence of solvent would increase the effective mass of the transferring proton via interaction with the surrounding solvent dipoles, which in turn would reduce the tunneling contribution according to the tunneling probability (P) expression defined above.