Stabilization and acidity

[Cecilia Lei 3K]

I think Professor Lavelle mentioned that acids are more readily lose H+ is the resulting anion is stabilized by resonance and/or electron withdrawing atoms which delocalize and stabilize the negative charge. What does that mean? Can someone give an example?

[Aditya Desai 1A]

Think of, say, how HClO4 is a strong acid but HClO is weak. The ClO4- anion has resonance, and is thus very stable. ClO-, on the other hand, has a localized negative on oxygen, and is less stable.