Aryl radical anions created in liquid alcohols decay on the microsecond time scale by transfer of protonsfrom the solvent.1,2 This paper reports a 4.5 decade range of rate constants for proton transfer from a singleweak acid, ethanol, to a series of unsubstituted aryl radical anions, Ar-. The rate constants correlate withfree energy change, G, despite wide variations in the two factors that contribute to G: (a) the reductionpotentials of the aryls and (b) the Ar-H bond strengths in the product radicals. For aryl radical anionscontaining CH2OH substituents, such as 2,2'-biphenyldimethanol- which is protonated with a rate constantof 3 × 109 s-1, the faster rates do not fit well in the free energy correlation, suggesting a change in mechanism.