Why HF is a weaker acid than HCl

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John_Richey_4A
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Why HF is a weaker acid than HCl

Postby John_Richey_4A » Sun Dec 09, 2018 2:00 pm

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?

AngelaZ 1J
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Re: Why HF is a weaker acid than HCl

Postby AngelaZ 1J » Sun Dec 09, 2018 3:07 pm

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.

marg44
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Re: Why HF is a weaker acid than HCl

Postby marg44 » Sun Dec 09, 2018 3:08 pm

I got this wrong on the test but that’s okay.

Dhwani Krishnan 1G
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Re: Why HF is a weaker acid than HCl

Postby Dhwani Krishnan 1G » Sun Dec 09, 2018 4:38 pm

By that same logic, would HClO2 be weaker than HClO3?

Rami_Z_AbuQubo_2K
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Re: Why HF is a weaker acid than HCl

Postby Rami_Z_AbuQubo_2K » Sun Dec 09, 2018 5:03 pm

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

Alli Hinmon 3E
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Re: Why HF is a weaker acid than HCl

Postby Alli Hinmon 3E » Sun Dec 09, 2018 5:33 pm

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.

Anjali_Kumar1F
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Re: Why HF is a weaker acid than HCl

Postby Anjali_Kumar1F » Sun Dec 09, 2018 5:35 pm

Why is it when there is more oxygen then the bond is more acidic?

Lynsea_Southwick_2K
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Re: Why HF is a weaker acid than HCl

Postby Lynsea_Southwick_2K » Sun Dec 09, 2018 5:45 pm

Because of the length of the bond

Nathan Tran 4K
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Re: Why HF is a weaker acid than HCl

Postby Nathan Tran 4K » Sun Dec 09, 2018 6:10 pm

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.

Grace Diaz 3F
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Re: Why HF is a weaker acid than HCl

Postby Grace Diaz 3F » Sun Dec 09, 2018 7:18 pm

HCL has a greater bond length making it easier for H+ to disassociate making it a stronger acid.

404982241
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Re: Why HF is a weaker acid than HCl

Postby 404982241 » Sun Dec 09, 2018 11:25 pm

F is too electronegative to have HF be a strong acid. It retains the hydrogen to well and does not fully disassociate in water

405021651
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Re: Why HF is a weaker acid than HCl

Postby 405021651 » Sun Dec 09, 2018 11:34 pm

does a bigger radius mean a stronger acid or is it the other way around??

Bella Martin
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Re: Why HF is a weaker acid than HCl

Postby Bella Martin » Tue Jul 30, 2019 10:37 pm

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


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