Strength of HF

[Miles John-Baptiste 3C]

Why is HF not a strong acid like the rest of the halogens?

[smrithi n]

The strength of the acid is dependent on how strong the bond is between H and A. The stronger that bond, the less the acid can dissociate, and the weaker the acid is. An HF bond has hydrogen bonding, making it stronger than the rest of the halogens, and thus making it a weak acid.

[Timothy Liu 3C]

If you remember from Chem 14A, atomic radius increases as you go down a group. Fluorine is at the top of the group, making the bond length between Hydrogen and Fluorine very short, meaning the bond in HF is significantly stronger. A stronger bond makes it more difficult to break and produce more H+ or H3O+ in water.

[Alan Lee 2I]

In short, the Flourine atom is very strong making the bond length very short. Since the bond length is so short it doesn't break up/ dissociate very easily