Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: Evie on 02/06/2009 17:07:32
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Our chloridometer is on the fritz and my boss and I have been trying a few different methods for determining chlorides (mg Cl-/L) in the water we use here in the lab where I work.
The method we have been trying is an argenometric titration using silver nitrate and powder pillows or liquid potassium chromate as the indicator.
The main problem with that method is that the endpoint (color turns from yellow to pinkish-yellow) is very hard to determine. It's almost subjective, unless you did about 1000 standards and became an expert on the fine color change. Any ideas, suggestions, etc.? We're trying not to spend lots of money to get a new chloridometer or probe for other meters.
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About a million years ago my dad did this titration using a silver/ silver chloride electrode.
I don't remember the details but I know it's possible.
Another aproache is to measure AgCl gravimetrically but that's a total pain.
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Yeah, the electrode is how we usually do it, and that's the easiest way. We were just hoping there would be an alternate way that isn't a huge pain and doesn't cost a lot of money. Thanks for the reply!
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An Ag/AgCl electrode is nothing more than a bt of silver wire electrolytically coated with the chloride. It's possible to make one at fairly low cost.