By Anonymous on Wednesday, June 16, 2004 - 07:20 am:
Hello,
I am interested in finding out how to analyse quantitively levels of NaOH in a water sample. I have been looking all over the place, but iam unable to locate any information. If anyone has any ideas please let me know.
Thanks
By Anonymous on Wednesday, June 16, 2004 - 08:04 am:
Titrate with standardized acid? Or am I missing something?
By Anonymous on Wednesday, June 16, 2004 - 08:39 am:
AAS for trace levels?
By Anonymous on Tuesday, June 22, 2004 - 01:59 am:
I am not a trained chemist, and sometimes the simplest of solution for a problem do not appear.
I have been thinking about a conductivity based method, but once again my lack of 'real' chemistry is letting me down.
If you have any ideas regarding this or more information about teh tritration method, i would really appreciate it.
best regards
By Anonymous on Friday, June 25, 2004 - 05:35 am:
you put an indikator into your NaOH and titrate it with for example HCl with known konzentration
the volume HCl used for setting the NaOH neutral =Konzentration NaOH
By Russ on Friday, June 25, 2004 - 01:04 pm:
If there are any other bases in your sample solutions (carbonate, bicarbonate, amines, etc.), they could interfere with a hydroxide determination by titration or make picking an indicator difficult.
By tom jupille on Friday, June 25, 2004 - 04:08 pm:
Depends on what you're trying to do. If you're not a chemist, you have to realize that there is no such thing as "NaOH" in water. What you have is Na+ ions and OH- ions. Ions have no memory -- there is no difference between a Na+ ion that came from dissolving NaOH versus one that came from dissolving NaCl.
With that in mind:
The concentration of OH- ions is easily determined using a pH meter. If you are not a trained chemist, find a good introductory chemistry text and read the section on pH.
The concentration of Na+ ions can be determined in a number of ways:
- ion chromatography
- flame photometry
- ion-selective electrode
(to name just three).
If the *only* source of dissolved material is NaOH added to the water, then you can measure *either* Na+ or OH- and determine the concentration of NaOH dissolved in your water. You could also measure conductivity and calibrate with known concentrations of NaOH (which I assume is what you're suggesting).
Be careful, however: if there are other sources of ions (of any type), then the conductivity measurement will be useless. Likewise, if there are other sources of Na+ or OH-, then those measurements will also give misleading results.