SunriseSunset - 23-8-2015 at 20:51
In this video, this guy shows that from a diluted solution of Hypochlorous acid, he can use it's pH to determine the Ka.
https://www.youtube.com/watch?v=OA-f_8F5iNU
Once his instructions are completed, i took his result which is Ka = 3.47*10^-8
and used my calculator to find the negative log which gave me pKa = 7.46
Then when I look on wikipedia, it says the pKa of Hypochlorous acid is: 7.53
I'm wanting to be able to solve for Ka values from experimental data such as pH but is this minor margin of error still going to be accurate enough
for most eventual purposes? Maybe it would of been closer if he had a more accurate pH test. Anybody have suggestions? I don't know of any pH tests
that can determine more significant figures other than 0-14. The experimental pH he used for his calculation was already accurate down to 4.23 from a
0.1M solution. Thanks
What is the most accurate way to test pH that's out there? for being able to determine Ka values from a compound that doesn't have known data in
literature. So far the closest I've found are strips that go in .5 increments lol Is there any affordable product that yields .05 or .005 pH scale
accuracy?!
[Edited on 24-8-2015 by SunriseSunset]
DJF90 - 23-8-2015 at 22:16
A half decent pH probe will read to two decimal places. Be sure to calibrate before each use for accuracy.
DraconicAcid - 24-8-2015 at 06:02
A pH probe will read to two decimal places, but the actual pH will depend quite a bit on ionic strength, etc. The pH calculations taught in
first-year university courses is vastly simplified.
PHILOU Zrealone - 25-8-2015 at 05:09
Temperature is also important for pH just like CO2 in the air...this is especially true for weak acid-bases in the sensitive regio pH 6-8...