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Electronegativity and Acidity

Posted: Thu Dec 06, 2018 4:43 pm
by taywebb
The book says the greater the electronegativity of A, the stronger the acid HA is, however, F if the most electronegative element, but the book also says that HF is the weakest acid. Can someone explain why?

Re: Electronegativity and Acidity

Posted: Thu Dec 06, 2018 5:07 pm
by nolansheow3G
HF is a weak acid because fluorine is relatively small compared to the other atoms in its group. This makes the bond length shorter and therefore makes the H-F bond relatively strong. A stronger bond results in a weaker acid because HF is less likely to dissociate in to H+ and F-. I'm not exactly sure why the book says that greater electronegativity results in a stronger acid... if you search "electronegativity and acid strength", it says that the greater the electronegativity, the more concentrated electrons are and therefore the acid becomes weaker ...