Association of hydrofluoric acid in NaCl aqueous media under hydrothermal conditions

The apparent association constant of hydrofluoric acid Q_HF^' in 1m NaCl aqueous media has been determined potentiometrically at pressures up to 1 kbar and temperatures up to 250°C. A concentration cell employing hydrogen electrodes was used. The association of HF increases with increasing temperature but decreases with increasing pressure.