CHEMISTRY COMMUNITY

"Arrange the oxoacids of bromine according to strength: HBrO4, HBrO2, HBrO3, HBrO"

I understand the strongest acids have the most oxygens, but I was hoping somebody could expand on the reason for the oxygen weakening the strength of the OH bond. Why do more of them (Oxygens) decrease the strength of the H bond. Is it because of electronegativity or what??

Thank you in advance for your time in explaining this to me :)

I think more oxygens means the strength of the bond to hydrogen will decrease because of more resonance, basically more electron delocalization away from the hydrogen because more electronegative atoms are present.

You are right, the oxygens shift the electron density away from the hydrogen, due to their high electronegativity. This causes the O-H bond to weaken, allowing the H to be removed more easily, and making those oxoacids with more oxygens the stronger acids.

In class we were told that the oxygens were pulling at the H, making it so that the bonds are weakened. This has to do with the electronegativity. When the bonds are weak, an acid is being made stronger

Since oxygen is highly electronegative, it has a strong pull on the electron density. More oxygens would mean a larger pull on the electron density away from the hydrogen, weakening the bond between the hydrogen and the oxygen thus making it easier for the hydrogen to disassociate making it a stronger acid.

Yeah, basically by Br having its electrons in bonds with electronegative O atoms, its electrons become more shared in that region and are not so close to the Br itself. Rather than there being less O bound to the Br, in that case are more lone pairs on Br, which help use more of that negative charge near the H to keep the positive H tightly held. This lets the H break away less easily, making it less acidic.

I remember hearing that since O is pulling towards H, it means a weak bond. As you mentioned, their electronegativity is involved :)