Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: carbon on March 04, 2014, 11:55:08 PM
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Hello Forum Chemists
any body can guide me about purity procedure of NaCl (Sodium Chloride) or about chloride Test in NaCl (Sodium Chloride)
From
Carbon
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This is a pretty wide subject. What is the context of your question?
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this topic belong to inorganic chemistry .p/z solve my problem
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Sorry, but the question is quite ambiguous and it is not easy to answer not knowing what you are really looking for. We need more details.
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You could mix it with water and filter it. Weight it before and after, that would remove anything that can't dissolve in water. You may be left with other salts though.
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How can we identifiy purity by help of chemical titation?
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How can we identifiy purity by help of chemical titation?
That's a little bit more helpful. Although most of us are disappointed it to so long to get to this point. You'd like to quantitate sodium chloride by titration. Good. The canonical method is to use silver nitrate. Now we have to figure out how you will determine the end point -- colorimetrically, or potentiometrically. This all depends on the instruments and reagents you have handy, and your own technical ability. It would be useful to know what limits you're looking to detect, and why you need that level. And a few other things too, like accuracy and precision requirements, but you can tell us that later.
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yes normally chemist use Silver Nitrate (for Titration) and Pottsium chromate as a indicator but main problem is end point of this titration .
Normally sodium Chloride purity we are getting 94% to 99.8 (it is depend on process)
I am giving u youtube link there one technician performing Nacl purity but I am not undersanding b/c Technician using defferent indicator and also calculation is not mention
http://www.youtube.com/watch?v=XMaClYp-djA
from
Carbon
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I am giving u youtube link there one technician performing Nacl purity but I am not undersanding b/c Technician using defferent indicator and also calculation is not mention
Have you googled for Fajans method? I am sure it is explained somewhere.
Most commonly used methods are Mohr and Volhard:
http://www.titrations.info/precipitation-titration-argentometry-chlorides-Mohr
http://www.titrations.info/precipitation-titration-argentometry-chlorides-Volhard
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The YouTube link is using Farjan's method. The dichlorofluorescein is an easier indicator to use that chromate or thiosulfate. The calculation remains the same: you use the titer of your silver nitrate to determine the amount of chloride you have. What is your current method, and what specific problems are you having with it? You want 94-98% purity, what are you getting, and what is it a problem? A problem with your NaCl source? Or a technician problem? Have you review this page from Borek:'s site highlighting common titration pitfalls? http://www.titrations.info/titration-errors If you have high volume needs, you might want to look into purchasing an automated potentiometric titration system.
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Dear Chemists
Actually I am checking sodium chloride from salt lake and after refining. In salt lake normally salt show low purity due to impurities but after refining of salt impurities decrease from salt and salt show high purity.
My problem is that I am using silver nitrate and potassium chromate but I cannot getting end point of this titration and after calculation I got purity in percentage above 100 in refined salt.Mr Boreak gave me some link according to above mention link I think I am using Mohr method but Mohr and Volhard both are mention some specific pH environment and other chemical precipitation problem during titration and other fajans method may solve my problem but in fajan method how can I use indicator .is indicator available in market in prepared condition or I will prepared in lab b\c I searched about indicator in google and indicator available in two shapes liquid and solid state (in 5g Bottle¬
Is Borek mention methods can we use to identify purity of high purity salt 99.9 .
Mr Arkon can u explained how can I use automatic potentiometric titration to determine purity of salt and its accuracy if we compare to above mentioned methods
From
Carbon
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In the case of high purity salts correct approach is not to determine amount of the main component, but to measure amounts of impurities, and assume sample is "filled up" to 100% with thee main component.
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I'm also a little bit confused by your application. For example, I've done automated potentiometric titrations in the 100-500 ppm range. I've used Farjan's method to determine the titer of a chloride solution, using 0.5 g of chloride. I found it in the US Pharmacopeia, you may find it in another pharmacopeia. The solid is for sale, as is the indicator solution
You'll notice I'm analyzing very small amounts, of very pure chloride. If you want to analyze the total chloride ion of a salt lake sample or evaporated salts, you will have to dilute. Not that none of these methods are selective for sodium chloride, so if this is a salt lake sample, I'm not surprised you're finding interference giving you false high levels.
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Hello Chemists
I am taking 0.1 gm salt (Lake or refined or evaporated or pharma grade).add 25 ml distilled water and add 1 ml potassium chromate and titrate with silver nitrate but can’t find exact end point due to precipitation and color that’s why I am getting purity result above 100 %
Normally Salt Purity
1) Lake or Evaporated Salt : Below 98 %
2) Refined Salt Purity : 99% to 99.8%
3) Pharma Grade salt Purity: 99.9% to 99.98%
Can I analyze sodium chloride purity by help of potentiometeyr titration?
From
Carbon
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What is the exact procedure you follow?
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Could you not grow NaCl crystals to ensure purity?
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NO
due to open ground (open Area) crystallization process