Lecture 28 #1

[Claire_Kim_2F]

I was wondering why HF would stabilize the anion the most and be the strongest acid because I thought Hf would be the weakest because it is the hardest to break and would not disassociate as easily as the other ones listed in the chart?

[Lillian Ma 1I]

Fluorine is the most electronegative which means it pulls the electrons towards it when it is in the compound which in a way means that the H that will be removed contributes less electrons to the compound. This means that the anion left behind is more stable because it was already slightly negative to start with.

[Victor Li 2A]

I thought the lecture stated that HF is a weak acid since the bond between H and F is very strong and short, thus harder to dissociate and donate H+. In terms of acidic strength: HF < HCl < HBr < HI.

[Benjamin_Hugh_3F]

I am also slightly confused because HF is known to be a weak acid, but sharing my second thought if we look at it from a relation between acid and conjugate base, a stable(weaker) conjugate base means it has a strong acid. If you look at the equation: HF + H20 --> F- + H30+, F- is a stable conjugate base; thus, HF would be a strong acid.

[Kiyoka Kim 3C]

I think the example is showing how the fluorine atom in the acid (not HF) is stabilizing the anion because it has high electron withdrawing ability.

[Alexandra Salata 2L]

Bond strength is related to the length of the bond, and because Iodine has a much larger atomic radius than Fluorine, HI has a much longer, and therefore weaker, bond. The hydrogen is removed fairly easily, making HI a stronger acid