I've got to calculate the pI and pKa values of an amino-acid.
In the lab two separate titration's were done: one with HCl till pH 1.5 and one with NaOH till pH 11.5. I know the concentration of NaOH and HCl.
Now I've got to create a graph pH versus moles base added (do they mean equivalents OH- added?) but I've got no clue where to start.
The moles base added makes sense for NaOH but I don't understand how this work for HCl and even less how to combine the data of both titrations.
Would be extremely grateful is someone can point me in the right direction.

Question

I've got to calculate the pI and pKa values of an amino-acid.
In the lab two separate titration's were done: one with HCl till pH 1.5 and one with NaOH till pH 11.5.  I know the concentration of NaOH and HCl.
Now I've got to create a graph pH versus moles base added (do they mean equivalents OH- added?) but I've got no clue where to start.
The moles base added makes sense for NaOH but I don't understand how this work for HCl and even less how to combine the data of both titrations.
Would be extremely grateful is someone can point me in the right direction.

anonymous · Answer

no-one :(?

anonymous · Answer

You need to create a titration curve! However, I have not done it in so long that I don't want to steer you in the wrong direction so, here are a few links that hopefully help! http://vlab.amrita.edu/?sub=3&brch=63&sim=1336&cnt=1 http://www.chem.illinois.edu/CLCtutorials/104/AminoAcidTitrations/SeeIt.html http://faculty.northseattle.edu/tfurutani/che103/lab4.pdf I hope this helps at least a little, hopefully visualizing the different titration curves will help you figure out exactly how to plot yours! Good Luck!

anonymous · Answer

Thanks jerrijones, unfortunately i've found those links too but they didn't really help :(