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NaOH & KOH titration procedure interchangeable?
November 5, 2012
Q. I have a simple colorimetric titration that we perform on our NaOH tank for determining concentration in oz/gal.
Could I use the same titration for a KOH tank that we may be installing?
Marc Green
anodizer - Boise, Idaho
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November 6, 2012 A. The procedure will be the same. The fudge factor will be slightly different due to the wt of the Na ion vs the K ion. James Watts- Navarre, Florida November 7, 2012 It will not be the same. Even though the molar ratios might be the same, the g/mol of KOH is higher than the g/mol of NaOH by a factor of 1.4.
- Eastman, Georgia, USA November 7, 2012 A. Good day Mark. - Toronto, Ontario, Canada |
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November 8, 2012 A. Hello, - Cañuelas, Buenos Aires, Argentina A. The titration procedure would remain the same since both KOH and NaOH are such strong bases. However, the calculation would change. V1 x N1 = V2 x N2, where V! is volume of titrant, N1 is normality of titrant, V2 is volume of sample, and N2 is normality of sample.  James Totter, CEF - Tallahassee, Florida November 8, 2012 |
A. Scott's answer is wrong. ml x N = ml x N. If the N is the same, then the ml has to be the same. Now the weight of the hydroxide to get a 1N solution will be different by the 1.4xx factor mentioned.
For a tank analysis, you do not know the N of the OH, so you multiply the ml of acid by an appropriate fudge factor to get the amount of whichever OH you are using.
His first sentence is correct.
- Navarre, Florida
My apologies, its been a while since my college chem class and obviously I should be more careful.
Scott Merritt- Fort Walton, Florida, USA
Q. Gentlemen, thank you very much. I consider myself very good at what I do, however chemistry is definitely a weak point for me (one of those things you think "yeah, I'll never use this crap in real world" while sitting in class). So I'd like to make sure I understand what you guys are telling me. My current titration for the NaOH is as follows:
2 ml of NaOH solution diluted to 5 ml with DI water
Couple drops of phenolphthalein
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Amazon [affil links]
Titrate to phenolphthalein end point with 0.1N HCl
ml of .1N HCl x 3 = concentration of NaOH in oz/gal
So, if I'm understanding correctly, instead of multiplying times 3, I should multiply times 4.2 (3 x 1.4) in order to get my concentration?
Marc Green
anodizer - Boise, Idaho
November 13, 2012
A. Good day Mark.
I have not seen/am familiar with your titration, but as long as you are confident with it (I always make known standards and analyze to verify a different/new analysis), continue.
I use a 10 ml sample with barium chloride, phenol, 0.1N HCl, filter, methyl orange
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, 1.0N HCl.
This procedure gives me both OH & CO3 in one analysis for Na & K.
The factor for NaOH is 0.053 and the factor for KOH is 0.075.
Yes, the KOH factor is 1.415 times the factor for NaOH.
Oh, and yeah, I think I'm pretty good at what I do, yeah, I started out as a plater, "helped" out in waste treatment, and "helped" out in the lab, and now years later the lab is where I "help" out the platers!
Hope this helps.
Regards,
- Toronto, Ontario, Canada
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