## H-F, H-Cl, H-Br, and H-I

Acidity $K_{a}$
Basicity $K_{b}$
The Conjugate Seesaw $K_{a}\times K_{b}=K_{w}$

Michelle N - 2C
Posts: 117
Joined: Wed Sep 18, 2019 12:19 am

### H-F, H-Cl, H-Br, and H-I

H - F
H -- Cl
H --- Br
H ---- I

H-F is the weakest of something? My apologies if this is very out of context, but can someone help me out on this? I'd very much appreciate it.

xenamclean_1G
Posts: 51
Joined: Sat Jul 20, 2019 12:15 am

### Re: H-F, H-Cl, H-Br, and H-I

H-F was the weakest acid because it has the shortest, strongest bond. The acids get stronger down that list (the longer the bond gets.)

Christineg1G
Posts: 115
Joined: Fri Aug 09, 2019 12:15 am
Been upvoted: 1 time

### Re: H-F, H-Cl, H-Br, and H-I

Remember that bond length increases with atomic radius. So, the longer the bond is between two elements, the stronger the acid is. For example, H-I has the longest bond, so it will be the strongest acid. And vice versa, the shorter the bond is, the weaker the acid is. So, H-F would be the weakest acid out of the ones you listed since it has the shortest bond.
Hope this helps!

Paul Hage 2G
Posts: 105
Joined: Thu Jul 25, 2019 12:17 am

### Re: H-F, H-Cl, H-Br, and H-I

Acid strength is based on how easily the molecule can give off a proton. Because HF has the shortest and therefore strongest bond, it would be somewhat difficult to break the H+ off the molecule, whereas the relatively long bonds in HCl, HBr, and HI make it easier for the molecules to give off a proton in solution.