polyprotic acids

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Elizabeth Harty 1A
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polyprotic acids

Postby Elizabeth Harty 1A » Sat Dec 07, 2019 11:45 am

Why is it that the Ka is bigger for the first dissociation in comparison to the second?

Joowon Seo 3A
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Re: polyprotic acids

Postby Joowon Seo 3A » Sat Dec 07, 2019 12:47 pm

Because it is easier for the first hydrogen to be dissociated from the acid. The atom holds on to the second and the third protons more tightly than the first.

Adam Kramer 1A
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Re: polyprotic acids

Postby Adam Kramer 1A » Sat Dec 07, 2019 1:35 pm

When you get rid of the first proton, there is more of a negative charge, holding the rest of the protons in a stronger bond, therefore making it harder to dissociate. This makes it take more energy to break the bond and therefore makes the Ka smaller for each successive dissociation.

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Re: polyprotic acids

Postby rohun2H » Sat Dec 07, 2019 10:19 pm

The negative charge created after the first dissociation makes it more difficult for the second dissociation to occur.

Libby Dillon - 1A
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Re: polyprotic acids

Postby Libby Dillon - 1A » Wed Dec 09, 2020 11:50 am

The Ka value for the first reaction does not involve any negatively charged ions in the example we did during lecture. This means the proton is not as tightly held as it will be in the second reaction, which involves a negatively charged ion. The proton will be more tightly held in the second reaction and the Ka2 value will be lower.

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Re: polyprotic acids

Postby DMaya_2G » Wed Dec 09, 2020 8:35 pm

The first proton to dissociate is the most strongly acidic, followed by the order in the next most strongly acidic proton.

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