pH and pKa

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Allan Nguyen 2G
Posts: 100
Joined: Wed Sep 30, 2020 9:49 pm

pH and pKa

Postby Allan Nguyen 2G » Wed Jan 13, 2021 10:02 pm

I know that they're both different, but how can I differentiate between the two in terms of application and concepts?

Kaley Qin 1F
Posts: 96
Joined: Wed Sep 30, 2020 9:54 pm

Re: pH and pKa

Postby Kaley Qin 1F » Wed Jan 13, 2021 10:05 pm

It just depends on what the question is asking. If it asks for equilibrium or a constant, use pKa. If it asks for a concentration or anything related to concentration use pH.

Katie Nye 2F
Posts: 95
Joined: Wed Sep 30, 2020 9:55 pm

Re: pH and pKa

Postby Katie Nye 2F » Wed Jan 13, 2021 10:25 pm

Both refer to acids and bases but pKa is specifically related to dissociation and how much the substance will dissociate in water while pH is simply the acidity of the substance.

Aishwarya Kosgi 1F
Posts: 97
Joined: Wed Sep 30, 2020 10:00 pm

Re: pH and pKa

Postby Aishwarya Kosgi 1F » Wed Jan 13, 2021 10:33 pm

Hi! Adding on to this question, is pH associated with strong acids/bases and is pKa associated with weak acids/bases? I think I remember learning that if a reaction has a Ka/Kb value, that means it is a weak acid/base. If anyone could clarify, that would be great! Thanks!

BrittneyMyint1D
Posts: 115
Joined: Wed Sep 30, 2020 9:59 pm
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Re: pH and pKa

Postby BrittneyMyint1D » Wed Jan 13, 2021 11:45 pm

Hi, I believe that pH would be more used for showing the concentration of H3O+ since pH is gotten from -log[H3O+] while pKa is more related to dissociation of the acid since it's gotten from -log(Ka). It may also depend on the information given and what the question is asking. Hope this helps!

Pranav Daggubati 3C
Posts: 118
Joined: Wed Sep 30, 2020 9:35 pm

Re: pH and pKa

Postby Pranav Daggubati 3C » Thu Jan 14, 2021 8:20 am

An easy way to think about it would be to think of p as a modifier that states the relative amount of things that are released. pH is then a measure of the number of H3O+ ions that are created when something dissolves. pKa would be the measure of the relative number of disassociations that happen when and acid is dissolved.

Mary Shih 3J
Posts: 101
Joined: Wed Sep 30, 2020 9:39 pm

Re: pH and pKa

Postby Mary Shih 3J » Thu Jan 14, 2021 1:35 pm

PH= tells us how acidic something is (can indirectly tell you how basic it is also)
Pka= dissociation of acid or base


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