The measured 𝑘𝑘 0 of ~3 cm/s is comparable to the measured standard rate constant for some types of metal-deposition reactions, and roughly an order of magnitude larger than what has been reported for the Fe(CN)6 3-/Fe(CN)6 4-couple. The 𝑘𝑘 0 of ~3 cm/s found here, however, should be interpreted as an apparent lower bound on the standard rate constant for proton-transfer at the ITIES given that the fit equation differs very little from the diffusion-limited case (Figure ). It is possible that proton transfer across the ITIES is considerably faster than can be reliably measured by electrochemical methods alone, and given the importance of ion transfer in electrochemistry we should try to explain why this is so. Overall, the kinetics of proton transfer are hypothesized to be controlled by the aggregation of many small partial desolvation steps as it moves through the mixed solvent interphase region.