Strength of Acids

[Farah Abumeri 3F]

In today's lecture (Dec 2nd), Dr. Lavelle was comparing the strength of two strong acids: HBr and HCl. Is an acid with a weaker bond (which in this case is HBr, since it is larger) a stronger acid because it can give away a H+ to form H3O+ more easily? I was confused whether HCl or HBr was the stronger acid. Thanks in advance!

[Arielle Sass 2A]

Hi, you're right that HBr is a stronger acid than HCl, because it has a weaker bond so it dissociates more easily, causing it to give off more H+ ions in the solution. In the scheme of all acids though, I think both HBr and HCl are considered strong.

[Sabrina Galvan 3J]

Yes! Because Br is larger, it has a weaker bond to H, allowing it to dissociate more easily and completely, as all strong acids are assumed to completely dissociate within a solution.

[Maaria Abdel-Moneim 2G]

HBr is the stronger acid. Since Br is larger than Cl the bond length of HBr is larger making it a weaker bond. This allows the bond to break much easier and therefore it can more easily donate H+ compared to HCl.

[alebenavides]

yes br is a stronger acid !

[Michael Sun Dis 3G]

HBr is indeed stronger, as it dissociates more easily than HCl, resulting in a higher concentration of H+ in solution.

[Jiapeng Han 1C]

HBr is the stronger acid because it has longer H-A bond, so weaker attraction between H and Br, thus proton is more easily dissociated.

[Jason_John_2F]

acids are stronger when they can easily dissociate in water and since br has a longer and weaker bond then it makes the stronger acid

[Simi Kapila_3E]

Yes, you're right, since Br is a bigger atom, it is farther away from H, making the bond length longer, and thus creating a weaker bond. Since it is a weaker bond, it is easier to dissociate the molecule and create hydronium ions.