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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: profmsg on December 28, 2006, 03:10:19 PM

Title: degree of ionization
Post by: profmsg on December 28, 2006, 03:10:19 PM
hey
anybody know how to calculate the degree of ionization at pka 3 and ph 4
Title: Re: degree of ionization
Post by: Borek on December 28, 2006, 03:16:59 PM
Please read forum rules (http://www.chemicalforums.com/index.php?page=forumrules).

Calculate pH, assume [A-] = [H+] and use degree of dissociation definition.
Title: Re: degree of ionization
Post by: profmsg on December 28, 2006, 03:21:48 PM
can u calculate the degree of ionization of codeine at pka8.2 in the solution of ph 2
Title: Re: degree of ionization
Post by: Borek on December 28, 2006, 03:44:36 PM
Stop. That's what happens when you do three things at the same time. pH is given. Will take a look later.

Please don't post similar questions in separate threads - and please read forum rules (http://www.chemicalforums.com/index.php?page=forumrules).

Edit: OK. Find A/HA ratio from dissociation constant definition, express ionization degree with A and HA, then you need some simple math to get rid of A and HA (only their ratio is present in the final expression).
Title: Re: degree of ionization
Post by: chiralic on December 29, 2006, 07:20:53 AM
Also, read this link:

http://www.raell.demon.co.uk/chem/logp/logppka.htm (check section 1.4 pKa or dissociation constant)

Regards,

Chiralic
Title: Re: degree of ionization
Post by: Borek on December 29, 2006, 12:00:03 PM
Well, when it comes to links, pH calculation lectures (http://www.chembuddy.com/?left=pH-calculation&right=toc) are much more complete :)