pKa vs pH?

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Michelle Wang 4I
Posts: 63
Joined: Fri Sep 28, 2018 12:27 am

pKa vs pH?

Postby Michelle Wang 4I » Sun Jan 20, 2019 1:58 pm

I'm kinda confused by the different between pKa and pH/pKb and pOH. Are they basically the same thing?

Adrian C 1D
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

Re: pKa vs pH?

Postby Adrian C 1D » Sun Jan 20, 2019 2:37 pm

pKa and pH are not really the same thing, however, they work very similarly. The p in front of the Ka and [H+] just means to take the negative log of whatever comes after. So its the negative log of Ka and [H]. The method to turn pKa and pH are just about the same, you would just do 10^neg of either one to get the Ka or [H]. With Ka and [H+], you can find Kb and [OH-] via the Kw.

Albert Duong 4C
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Joined: Fri Sep 28, 2018 12:17 am
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Re: pKa vs pH?

Postby Albert Duong 4C » Sun Jan 20, 2019 3:02 pm

Basically, Ka is the equilibrium constant for acid ionization (a large Ka indicates a stronger acid that has dissociated completely) and correlates with a high concentration of H+. pKa and pH are just simpler ways of expressing this by taking the -log of each.

Amar Singh
Posts: 31
Joined: Fri Sep 28, 2018 12:20 am

Re: pKa vs pH?

Postby Amar Singh » Sun Jan 20, 2019 3:20 pm

The simple way to look at is the Ka is the equilibrum concentration and if you take the -log of it, you get the pH. Same for pKb/pOH. To convert it make, simply take the 10^-(pH/pOH) to find the pKa/pKb

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