Strongest oxoacid

[Raiden2012]

---

Members don't see this ad.

Rank the oxoacids in terms of strength
Strongest to weakest

HBrO, HIO, HClO

Reason?

 

[Singhp03]

well, what i know from reading is that when dealing with oxoacids, acid strength is not determined by bond strength like it would be in HBr vs. HCl but is instead dependent on electroneg(bc the acid H is attached to the O) and number of oxygens in the molecule . "With the same central atom E, acid strength increases as the number of oxygen attached to E increases. With the same number of oxygens around E, acid strength increases with the electronegativity of E(wiki)."

In the examples you indicated, I would expect the order to be HClO>HBrO> HIO in terms of acidity

 

[Fivo]

Since they all contain 1 O, the next indicator is the Electronegativity of the central atom. The higher the EN-, the stronger the acid in this case

^
Just noticed he said the same thing, brb slittingwrists

 

[Raiden2012]

Thx for the reply. So the difference between the trends for oxoacids and hydrogen halides is not comparable right? I mean the conjugate base F- is more electronegative than bottom halides. But I'm guessing the covalent bond for hydrogen halides is a bigger factor, thus making the comparison moot?

 

[Fivo]

Thx for the reply. So the difference between the trends for oxoacids and hydrogen halides is not comparable right? I mean the conjugate base F- is more electronegative than bottom halides. But I'm guessing the covalent bond for hydrogen halides is a bigger factor, thus making the comparison moot?

Correct. For Hydrogen Halides, the primary factor is the size of the halide. In short (per TBR), the bigger the halide, the longer the bond, the weaker the bond, the easier to break and dissociate, the stronger the acid.

 

[Raiden2012]

Correct. For Hydrogen Halides, the primary factor is the size of the halide. In short (per TBR), the bigger the halide, the longer the bond, the weaker the bond, the easier to break and dissociate, the stronger the acid.

Just curious, when HClO, HIO, HBrO dissociates, why don't we take into account the bond length as well.

I mean the lewis structure places the H next to the halogen atom as well. Or am I overthinking this (like always)

 

[Singhp03]

Just curious, when HClO, HIO, HBrO dissociates, why don't we take into account the bond length as well.

I mean the lewis structure places the H next to the halogen atom as well. Or am I overthinking this (like always)

i think your over thinking it, bc the O is connected to H and X bond length is pretty much irrelevant, or at the very least constant, in comparing acidity

 

[Donald Juan]

Just curious, when HClO, HIO, HBrO dissociates, why don't we take into account the bond length as well.

I mean the lewis structure places the H next to the halogen atom as well. Or am I overthinking this (like always)

Remember that it's not just bond length that determines how likely a bond is to break. One of the reasons HI is stronger is because the iodide ion is larger and able to stabilize the negative charge better than the smaller halides.

With that being said, I believe you are mistaken about the lewis structure. Any HXO acid should have a lewis structure like X--OH, so the more electronegative halide is better able to stabilize the negative charge of the conjugate base.

 

[Raiden2012]

Thanks peeps