Investigations have been made into the nature of the carbanions formed on the ionisation of certain carbon acids in aqueous-hydroxide and alcohol-alkoxide media. The interaction between solvent and carbanion is discussed in terms of the observed kinetic behaviour. A method has been developed for studying parallel detritiation reactions. Tritium nuclear magnetic resonance spectroscopy and radio-gas chromatography were used in conjunction with standard computing techniques to provide a reliable analysis of the kinetic data. This technique has been applied to a number of carbon acid mixtures, an unsymmetrical ketone and a steroid, tritiated at two distinct sites in each system. A kinetic study in a range of non-aqueous solvents has been carried out using a modified detritiation technique. The role of the solvent in the detritiation of [3]H diethyl malonate by heterocyclic bases is discussed and a mechanism assigned to the exchange reaction. The kinetics of ionisation of a number of nitroalkanes have been studied in highly basic media. Correlations between rate and acidity function have been made and interpreted in terms of transition state structure. The inverse relationship between thermodynamic and kinetic acidities is discussed.