Q

If HF is a weak acid, what can be inferred about the strength of its conjugate base F-?

RRB NTPC (G) CBT-1, 19-Jun-25 S-1 2025
✓ Answer: C It is a weak base.
If HF is a weak acid, its conjugate base F- is a weak base. If HF (hydrofluoric acid) is a weak acid, it means it does not dissociate completely in water. However, in the context of acid-base theory, a strong acid has a very weak conjugate base and a weak acid has a stronger conjugate base. So, while F- is stronger than the conjugate base of a strong acid, it is still not a strong base like OH- or O2-. It's classified as a weak base.