Page 1 of 1

Lewis Acid

Posted: Sat Dec 08, 2018 10:07 pm
by Nicholas Le 4H
Why is HBr a stronger acid than HF?

Re: Lewis Acid

Posted: Sat Dec 08, 2018 10:08 pm
by Christopher Wendland 4F
HF is extremely electronegative so it will hold onto its H and not dissolute completely in solution, however Br is lower on the periodic table and less electronegative so it loses its H in water.

Re: Lewis Acid

Posted: Sat Dec 08, 2018 10:08 pm
by Vanadium Wang 4H
HBr is a stronger acid than HF because Br is a larger atom than F meaning the bond length between H and F is closer than H and Br. That means HBr is more likely to dissociate and a strong acid more readily dissociates in water.

Re: Lewis Acid

Posted: Sat Dec 08, 2018 10:09 pm
by Caitlin_Murphy_3C
The strength of an acid depends on how easily the A-H bond can be broken. The stronger the acid, the weaker the bond. So, HBr is a stronger acid than HF because the atomic radius of Br is larger than the atomic radius of F, so the bond is longer (therefore weaker) and more easily broken.

Re: Lewis Acid

Posted: Sat Dec 08, 2018 10:09 pm
by chris_tsai_4H
HF has a stronger bond due to the higher difference in electronegativity therefore the bond is harder to break, meaning the proton is harder to donate. Therefore, HBr is a stronger acid since it has a weaker bond and can more easily donate a proton.

Re: Lewis Acid

Posted: Sat Dec 08, 2018 10:11 pm
by Harshita Talkad 4L
HBr has a greater bond length because Br has a greater atomic radius than F, which means it is easier for HBr to donate a proton, so it is a stronger acid.

Re: Lewis Acid

Posted: Sat Dec 08, 2018 10:16 pm
by Ashish Verma 2I
Bromine is in Group 4 of the Periodic Table while Fluorine is in Group 2. Based on periodic trends and atomic mass, Bromine is a heavier atom with a much larger atomic radius. As such, the single bond in HBr is much longer than the single bond in HF. Longer bonds are weaker so hydrobromic acid has a weaker bond and it is therefore much easier for it to lose its H+ ion and behave as an acid, making it a stronger acid relative to HF.