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Why HF is a weaker acid than HCl

Posted: Sun Dec 09, 2018 2:00 pm
by John_Richey_4A
Why is HF a weaker acid than HCl. I understand it has to do with the electronegativity being higher, but if thats the case, why is HClO a stronger acid than HBrO?

Re: Why HF is a weaker acid than HCl

Posted: Sun Dec 09, 2018 3:07 pm
by AngelaZ 1J
HCl is a stronger acid because the bond between H and Cl is weaker than the bond between H and F (this is because Cl has a greater atomic radius). HClO is a stronger acid than HBrO because the resulting anion of HClO is more stable as a result of Cl having a greater electron withdrawing power than Br.

Re: Why HF is a weaker acid than HCl

Posted: Sun Dec 09, 2018 3:08 pm
by marg44
I got this wrong on the test but that’s okay.

Re: Why HF is a weaker acid than HCl

Posted: Sun Dec 09, 2018 4:38 pm
by Dhwani Krishnan 1G
By that same logic, would HClO2 be weaker than HClO3?

Re: Why HF is a weaker acid than HCl

Posted: Sun Dec 09, 2018 5:03 pm
by Rami_Z_AbuQubo_2K
In this case, you are looking at the HF bond length vs the HCL bong length. Since Florine is more elctronegative than Cl, it will have a stronger pull on the H make it harder to donate the H. The longer the bond, the easier it is to remove the H. It follows one of three rules in the book for stronger acids

Re: Why HF is a weaker acid than HCl

Posted: Sun Dec 09, 2018 5:33 pm
by Alli Hinmon 3E
Because there is no O present, think of it as simple terms. H attached to an F that is small in radius is going to have a short bond, But CLs radius is bigger so longer bond, more easily broke, more acidic.

Re: Why HF is a weaker acid than HCl

Posted: Sun Dec 09, 2018 5:35 pm
by Anjali_Kumar1F
Why is it when there is more oxygen then the bond is more acidic?

Re: Why HF is a weaker acid than HCl

Posted: Sun Dec 09, 2018 5:45 pm
by Lynsea_Southwick_2K
Because of the length of the bond

Re: Why HF is a weaker acid than HCl

Posted: Sun Dec 09, 2018 6:10 pm
by Nathan Tran 4K
This comparison is different because in your first comparison, you are comparing bond lengths, but in your second comparison, you are comparing the electronegativity. The reason why we compare electronegativity in your latter comparison is because H is attached to O in both molecules; thus, comparing the bond lengths won't do you anything. You need to look at the electronegativity, or dipole, in order to determine how stable the anion will be after the hydrogen proton is donated.

Re: Why HF is a weaker acid than HCl

Posted: Sun Dec 09, 2018 7:18 pm
by Grace Diaz 3F
HCL has a greater bond length making it easier for H+ to disassociate making it a stronger acid.

Re: Why HF is a weaker acid than HCl

Posted: Sun Dec 09, 2018 11:25 pm
by 404982241
F is too electronegative to have HF be a strong acid. It retains the hydrogen to well and does not fully disassociate in water

Re: Why HF is a weaker acid than HCl

Posted: Sun Dec 09, 2018 11:34 pm
by 405021651
does a bigger radius mean a stronger acid or is it the other way around??

Re: Why HF is a weaker acid than HCl

Posted: Tue Jul 30, 2019 10:37 pm
by Bella Martin
405021651 wrote:does a bigger radius mean a stronger acid or is it the other way around??

I would think so because it would be easier to break the bond of a larger atom since the electrons are able to get farther from the nucleus