First of, Hydrofluoric acid is considered a weak acid, although it causes a lot of damage (it is used to etch glass). But, if that is how the problem was stated, I guess it can still be answered.
Acids, by definition, produce hydrogen ions. And, if you remember pH, the higher the concentration of hydrogen ions, the closer to 1 the number becomes. So, if you dissolve HF in pure water you should get a pH less than 7.
Acids, by definition, produce hydrogen ions. And, if you remember pH, the higher the concentration of hydrogen ions, the closer to 1 the number becomes. So, if you dissolve HF in pure water you should get a pH less than 7.