Ph and Pka

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Ph and Pka

Postby 204929947 » Sun Jan 27, 2019 8:20 pm

How do you go from PH to Pka and vice versa?

Dhwani Krishnan 1G
Posts: 63
Joined: Fri Sep 28, 2018 12:17 am

Re: Ph and Pka

Postby Dhwani Krishnan 1G » Sun Jan 27, 2019 9:18 pm

You could use Pka and an ICE table if necessary to find [H3O+].

Lasya Gudipudi 1A
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Joined: Fri Sep 28, 2018 12:15 am

Re: Ph and Pka

Postby Lasya Gudipudi 1A » Sun Jan 27, 2019 9:32 pm

If you are given the pKa, you would have to use the ICE table to find the concentration of [H3O+] at equilibrium and then take the -log of that value to find pH.

Nathaniel 2E
Posts: 27
Joined: Mon Jun 25, 2018 3:00 am

Re: Ph and Pka

Postby Nathaniel 2E » Sun Jan 27, 2019 10:06 pm

Going from pH to pKa, take 10^-(pH) to get the hydronium ion concentration. Use that in your ICE table (it will end up being x) and solve for Ka. Take the negative log of Ka, and you have your pKa

Arta Kasaeian 2C
Posts: 30
Joined: Mon Jan 07, 2019 8:22 am

Re: Ph and Pka

Postby Arta Kasaeian 2C » Sun Jan 27, 2019 10:40 pm

If you get pH, you can easily get the concentration of H3O+, and then using the Ice Table you can calculate all the other values going into the pKa equation and calculate the value of pKa itself.

Tony Ong 3K
Posts: 63
Joined: Fri Sep 28, 2018 12:23 am

Re: Ph and Pka

Postby Tony Ong 3K » Sun Jan 27, 2019 11:19 pm

pKA usually deals more with weak acids which cannot dissociate fully as opposed to strong acids where we can automatically calculate the pH because we know it dissociates completely.

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