Electronegativity and Acid/Base strength?

[Alison Le 2E]

Hi everyone! How does electronegativity relate to the strength of an acid or base? Thanks!

[Autessa Anoosheh 3E]

I believe for acids if there is more than one atom attached to the hydrogen then the higher the electronegativity the stronger the acid, because the molecule is more stable. For acids where it is just one hydrogen attached to one atom (HBr, HF, HI) then I think the shorter the bond the weaker the acid.

[Rose Arcallana 2B]

For monatomic acids, like HF HCl HI, their strength is compared based on the bond lengths. I always think of acids based on their ability to lose a H+, the stronger the acid the easier it is to lose H+. So if the size/atomic radius of the increases, the easier it is for it to lose a H+, thus a stronger acid. The strongest: HI, then HCl, last HF (weak acid)

For polyatomic acids, like CH2FCOOH and CH2ICOOH, this is based on their electronegativity. As you know electronegativity is the ability to pull electrons, creating partial negative and positive charges. So in this case, the higher the electronegativity, the stronger the acid because the electronegativity of one atom pulling the electron from the H atom is high making it easier for that compound to lose the H+. Between CH2FCOOH and CH2ICOOH, CH2FCOOH is a stronger acid because they are almost identical except for the F and I, and we know F has a higher electronegativity than I. :)