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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?

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.

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

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

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

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.

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

Because of the length of the bond

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.

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

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

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

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

405021651 wrote:does a bigger radius mean a stronger acid or is it the other way around??

Yes that is correct.

Rami_Z_AbuQubo_2K wrote: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

Thank you so much!! I was a bit confused about this topic.

HF is a weaker acid because the strength of an acid is determined by how completely that acid will dissociate. Since the bond between HF is stronger than the bond between HCl, HCl will more completely dissociate which makes it a stronger acid.

Since Cl has larger radius, which means that the attraction between H and Cl is weaker, so HCl is more easily to lose the proton.

The bond between H and Cl is stronger than the one between H and F due to the fact that fluorine is less stable than chlorine and more prone to dissociate.