2. Relevant equations none 3. The attempt at a solution The hydration enthalpy of Floride ion is very high. We know that HF react violently with NaOH to form floride salt and water. The enthalphy of this reaction is greater than Neutralization enthalphy (H+ + OH-=H2O) of other acid base. That proves that the hydration enthalpy is sufficient enough to supply required energy for H-F bond breaking, beside producing extra heat. So I dont understand why HF dont ionise in water, where hydration enthalphy is large enough to promote ionization.