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HI or HCl: stronger acid

Posted: Wed Jun 13, 2018 7:17 pm
by Isabelle De Rego 1A
On the French toast exam (#28) it lists the answer as HI as the stronger acid.
I picked HCl because I thought that since HCl had more ionic properties, it would hog electrons and make it easier for H to disassociate in water. Wouldn't HI have a harder time doing so, and thus make it a weaker acid?

Re: HI or HCl: stronger acid

Posted: Wed Jun 13, 2018 8:39 pm
by JulietOttenberg-1C
HI has a larger atomic radius so it is dissociates easier than HCl

Re: HI or HCl: stronger acid

Posted: Wed Jun 13, 2018 8:48 pm
by Kara Justeson 1B
is this an exception to the general trend? Because I thought more electronegative atoms formed stronger acids.

Re: HI or HCl: stronger acid

Posted: Wed Jun 13, 2018 9:11 pm
by Andrew Evans - 1G
More electronegative what I would call "accessory atoms" would cause a stronger base. So when an H+ proton dissociates from an oxygen lets say, are there other electronegative atoms attached to that original molecule that will be able to pull that charge away from the O and distribute it among the rest of the molecule, stabilizing the new anion. This allows it to be a stronger base.

For acids it is not quite so and just because it is more ionic doesn't mean it's a stronger acid.

Re: HI or HCl: stronger acid

Posted: Thu Jun 14, 2018 5:45 pm
by Megan Phan 1K
HI would be the stronger acid, as iodine's atomic radius is much larger than Cl's. So iodine is more evenly distributed when ionized

Re: HI or HCl: stronger acid

Posted: Fri Nov 30, 2018 1:46 pm
by Bingcui Guo
How to define strong acid and weak acid depends on the easiness to lose an electron. Since the bond of H and I is easier to break than H and Cl, it is easier for HI to lose H+ and thus it is a stronger acid than HCl.

Re: HI or HCl: stronger acid

Posted: Sun Dec 02, 2018 1:04 pm
by 105002507
HI would be the stronger acid

Re: HI or HCl: stronger acid

Posted: Mon Dec 03, 2018 12:47 am
by Sang Hyoun Hong 3G
HI would be the stronger acid due to its larger atomic radius.

Re: HI or HCl: stronger acid

Posted: Mon Dec 03, 2018 2:52 pm
by Nawaphan Watanasirisuk 3B
HI has longer bond than HCl, making its bond weaker. Therefore it is easier for HI to lose H+, making it a stronger acid.