Negative ion tests order

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asdfghjkl18
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#1
Report Thread starter 3 years ago
#1
my textbook says that negative ions should be tested in the order: carbonates, sulfates, halides then checking for ammonium ions but I'm wondering what the reason is for this order, does anyone know?
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luce12341
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It's because when you test for carbonates it removes any carbonates present - you then use the solution created to test for sulfates because barium chloride that you add to the solution would also react with carbonates to make a white precipitate so it prevents a false positive occurring (because no carbonates present to react). You then do halides because you add silver nitrate that would make a white precipitate of silver sulfate with sulfate ions - also creating a false positive because the halide ions also make white(ish) precipitates with the silver nitrate. You would know that the precipitate must be of a halide ion because there are no sulfate ions present.
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asdfghjkl18
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#3
Report Thread starter 3 years ago
#3
thank you, that's really helpful!!!
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