[Oxostudent2020]

I'm looking for some help with a titration question -

If you have a titration chart with pH on the y axis and Volume on the x axis. can you calculate the Ka from the chart?

That is Ka = [H+][A-]/[HA]. If you have the pH you can calculate the AH at the starting point of the curve but can you use the pH at a point on the curve to find the [H+] and then from that calculate the [H-] to substitute into the equation?. When I do it I end up with some values in excess of 10^-14 and I'm not sure that's correct. I don't know the acid nor is it required from what I can tell.

Example -
HA = 10^-3 (pH = 1 from chart)
H+ = 10^-4 (pH = 2 from chart)
A- = 10^-10 (10^-14 - H+)

Substituting back into the formula you can derive a Ka value. The question is, is this theoreticall correct or am I completely wrong?

Thanks to anyone who can help.

[AWK]

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http://www.chemicalforums.com/index.php?topic=40492.0;topicseen