AbstractBase hydrolysis ofN‐acetylpyrrole (1a) involves formation of an anionic tetrahedral intermediate (2a). The equilibrium constant between these two species can be estimated by extrapolation based on the equilibrium constants for hydration ofN‐trichloroacetyl‐ andN‐trifluoroacetylpyrrole and the estimated pKafor deprotonation of the hydrates of these compounds. Inductive effects upon hydration and deprotonation of the hydrates were estimated by analogy with inductive effects upon the equilibrium reactions of chloral and acetaldehyde. The free energies of activation for formation and return of2aare approximately 16 and 12.5 Kcal mole−1respectively and for conversion of2ato products 11 Kcal mole−1in aq