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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: dpm on June 20, 2008, 08:36:38 PM

Title: What makes HClO a weaker acid than HClO2?
Post by: dpm on June 20, 2008, 08:36:38 PM
I see the general trend: the higher the oxidation state of the anion, the more acidic the molecule is (in general), but why? I imagine it has something to do with the net dipole and how tightly bound the H is to the Cl, but I just can't seem to wrap my head around it.

K(sub)a    for    HClO4 > HClO3 > HClO2 > HClO

Why?
Title: Re: What makes HClO a weaker acid than HClO2?
Post by: vhpk on June 20, 2008, 11:11:27 PM
I see the general trend: the higher the oxidation state of the anion, the more acidic the molecule is (in general), but why? I imagine it has something to do with the net dipole and how tightly bound the H is to the Cl, but I just can't seem to wrap my head around it.

K(sub)a    for    HClO4 > HClO3 > HClO2 > HClO

Why?
HClO -> H+ + ClO-
HClO2 -> H+ + ClO2-
O is a more electronegative element than chlorine, it's an electron-withdrawing group too, when it's attached to Cl atom, it will disperse the negative chare on oxygen atom adjacent to Cl, hence stabilise the anion -> the more dissociations, the more acidic property