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Oxoacid Strength

Posted: Sat Dec 07, 2019 7:27 pm
by ayushibanerjee06
Would HOF or HOCl be a stronger acid? Since oxoacid strength is based on electronegativity, shouldn't HOF be stronger than HOCl?

Re: Oxoacid Strength

Posted: Sat Dec 07, 2019 7:35 pm
by Alex Tchekanov Dis 2k
The HOCl bond is longer than the HOF bond. Therefore, since the stability and thus electronegativity doesn't matter, it is the length of the bond that does.

Re: Oxoacid Strength

Posted: Sat Dec 07, 2019 7:36 pm
by Sebastian Lee 1L
Yep, HOF is the stronger acid! When the acids dissociate and donate their proton, you will be left with the anions, FO- and ClO-. Since F is more electronegative it will be able to better delocalize the negative charge of the Oxygen by pulling the electrons closer to it. This delocalization/induction makes the anion more stable. Since the FO- anion is more stable HOF is more likely to stay dissociated and is therefore the stronger acid.

Remember that, in this case, bond length DOES NOT MATTER because both have OH bonds. The bond with the hydrogen is the SAME LENGTH in both of them.

Re: Oxoacid Strength

Posted: Sat Dec 07, 2019 10:38 pm
by Abigail_Hagen2G
Okay, that makes sense. So, when concerning bond lengths, it's the comparison between hydrogen and another atom.

Re: Oxoacid Strength

Posted: Sat Dec 07, 2019 11:00 pm
by Matt F
^Correct. Strength for oxoacids is based on the stability of the resulting anion, which is influenced by electronegativity (withdraws electron density) and resonance. Typically I would just look at which acid contains the more electronegative atom

Re: Oxoacid Strength

Posted: Sun Dec 08, 2019 6:36 pm
by Annie Ye
You would only look at bond lengths if it was with binary acids. For oxoacids, you would look at the electronegativity.

Re: Oxoacid Strength

Posted: Sun Dec 08, 2019 6:36 pm
by jisulee1C
HOCl would act as the stronger acid.