CHEMISTRY COMMUNITY

What is the relationship between structure or hybridization and acidity?

The greater the s-character of a hybrid orbital, the greater the acidity of the acid. So an acid with hybridization will be stronger than an acid with hybridization, and an acid with hybridization will be stronger than an acid with hybridization.

Is there a conceptual reason behind this? I understand the rule that with a greater s orbital, the higher acidity of the acid, but why is this exactly?

S-orbitals are closer to the nucleus than p-orbitals. So the more s-character a hybrid orbital has, the closer the electrons are to the atom. Such atoms are less willing to share their electron density (have greater electronegativity), and thus have greater acidic character.