phillyza
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NaCl electrolysis and measuring remaining chlorides with mohr method.
Hi, Im new to the forum and dont know if this is the correct place to post as I have posted this in the beginnings section as well.
Im doing NaCl electrolysis. Im starting out with approximately 1g/l salt solution which gives me 585 ppm chlorides when measured with the mohr silver
titration method.
Then activation takes places and Im producing Anolyte and Catholyte. Then I measure the Free Available Chlorine and the Chlorides in the Anolyte and I
get about 330ppm FAC and the residual chlorides is about 496 ppm with the Mohr titration.
This doesnt makes sense to me because I expected that starting chlorides - FAC = end chlorides, which is not the case. I expected that some of the
chlorides convert in chlorine components (FAC) and you just subtract the FAC from the starting chlorides to obtain end chlorides? In this example I
expected end chloride value in my Anolyte to be 255ppm (585 - 330). Any guidance on this?
Where have I got it wrong? Does the silver nitrate titration measures total Cl - meaning chlorides or chlorine components?
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phillyza
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Anyone? Any advice please?
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gdflp
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Silver Chlorate is an explosive and light sensitive chemical which, while soluble in water, will decompose at room temp to silver chloride, giving
falsely high readings for chloride concentration.
On a different note : Please be aware that double posting to raise the position of your thread is strongly discouraged.
[Edited on 10-4-2014 by gdflp]
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jock88
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What is 'free available Chlorine' and how do you measure it?
What is the pH of the solution.
There will be only three 'things' AFAIK in there (dissolved) if pH is high.
Sodium Chloride.
Sodium Hypochlorite.
Sodium Chlorate (if you have run for some time, how much I don't exactly know).
There may be some Chlorites too (just to contradict myself).
What is the solubility of Silver Chlorite and Silver Hypochlorite does anyone know? ie will they interfere with the Mohrs test?
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jock88
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and some Chlorine gas would have escaped too. This is what causes the pH to rise. Forgot to mention above.
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phillyza
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Firstly it is silver nitrate, not silver chlorate that is used in the Mohr method.
pH is near neutral at 6.5-7.0. we are aiming for Hypochlorous acid production. pH doesnt rise.
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unionised
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Nobody said that silver chlorate is used in the Mohr method.
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