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Mass spectrum of negative ions of trichloroacetic acid (TCA) in aqueous solution was obtained by mass spectrographic method of electrolyte solution electrospray in vacuum (ESESv). The TCA reactivity was neutralized by potassium hydroxide. The mass spectrum of TCA consists of the acid residue ions, (CCl 3 COO) − , hydrated by different number of water molecules. The (CCl 3 COO) − ion hydrated by two water molecules has the maximum intensity. The ESESv method can be helpful for determination of the composition electrolyte solutions in ecological studies.

The kinetics of the reaction between fluorine atoms and trifluoroacetic acid has been studied experimentally at T = 258–343 K. The overall reaction rate constant decreases with temperature: k1(T) = 1.09 × 10−12 exp((+1034 K)/T) cm3 molecule−1 s−1. The potential energy surface of the reaction has been studied using quantum chemistry. The results were used in transition state theory calculations of the temperature dependences of the rate constants of the two channels of the reaction. The abstraction channel ultimately producing HF is dominant at the experimental temperatures; the addition–elimination channel producing CF3 and CF(O)OH becomes important above 1000 K.

The most probable hydration numbers, n max , for halogen ions in liquid solutions have been determined by the mass spectrometric method of field evaporation of ions out of solution (FEIS): 2.5 (F − ), 2.0 (Cl − ), 1.5 (Br − ), 1.0 (I − ). The values of n max are similar to the hydration numbers determined by other methods based on the measurement of ion mobilities and are half as large as n max for the hydration of the same ions in water vapour. FEIS is the most direct and reliable method for studying the ion hydration in solutions.