HI or HCl: stronger acid

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Isabelle De Rego 1A
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HI or HCl: stronger acid

Postby Isabelle De Rego 1A » Wed Jun 13, 2018 7:17 pm

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?

JulietOttenberg-1C
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Re: HI or HCl: stronger acid

Postby JulietOttenberg-1C » Wed Jun 13, 2018 8:39 pm

HI has a larger atomic radius so it is dissociates easier than HCl

Kara Justeson 1B
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Re: HI or HCl: stronger acid

Postby Kara Justeson 1B » Wed Jun 13, 2018 8:48 pm

is this an exception to the general trend? Because I thought more electronegative atoms formed stronger acids.

Andrew Evans - 1G
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Re: HI or HCl: stronger acid

Postby Andrew Evans - 1G » Wed Jun 13, 2018 9:11 pm

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.

Megan Phan 1K
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Re: HI or HCl: stronger acid

Postby Megan Phan 1K » Thu Jun 14, 2018 5:45 pm

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

Bingcui Guo
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Re: HI or HCl: stronger acid

Postby Bingcui Guo » Fri Nov 30, 2018 1:46 pm

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.

105002507
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Re: HI or HCl: stronger acid

Postby 105002507 » Sun Dec 02, 2018 1:04 pm

HI would be the stronger acid

Sang Hyoun Hong 3G
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Re: HI or HCl: stronger acid

Postby Sang Hyoun Hong 3G » Mon Dec 03, 2018 12:47 am

HI would be the stronger acid due to its larger atomic radius.

Nawaphan Watanasirisuk 3B
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Re: HI or HCl: stronger acid

Postby Nawaphan Watanasirisuk 3B » Mon Dec 03, 2018 2:52 pm

HI has longer bond than HCl, making its bond weaker. Therefore it is easier for HI to lose H+, making it a stronger acid.


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