Second-order rate constants for the reactions of the phenylsulfinate ion PhSO(2)(-) with benzhydrylium ions Ar(2)CH(+) have been determined in DMSO, acetonitrile, and aqueous acetonitrile solution using laser-flash and stopped-flow techniques. The rate constants follow the correlation equation log k (20 degrees C) = s(N + E), which allows the determination of the nucleophile-specific parameters N and s for