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Topic: unknown solutions  (Read 3403 times)

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Offline sittinghawk

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unknown solutions
« on: November 25, 2008, 06:16:27 PM »
how can i distinguish ammonium chloride from sodium chloride if i can use 10 different solutions including: potassium nitrate, sulfuric acid, copper (II) nitrate, sodium chloride, silver nitrate, sodium hydroxide, barium nitrate, ammonium chloride, acetic acid, and phenolphthalein
all in aqueous solution

Offline enahs

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Re: unknown solutions
« Reply #1 on: November 25, 2008, 09:02:45 PM »
So you got a mixture of soluble salts. If you mix to soluble salts together, and it forms an insoluble salt it will precipitate out.

From your standard solubility table; you should be able to figure out which two compounds to and decide if it is ammonium chloride or sodium chloride, i.e. forms a percipitate (ya know, other then smelling it unless it is super super dilute).
 

Offline Borek

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Re: unknown solutions
« Reply #2 on: November 26, 2008, 03:05:29 AM »
Sorry Shane, but it won't work this way - there is no precipitate that can be used in this case to differentiate between NH4+ and Na+. However, NH4+ is a weak acid...
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Offline enahs

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Re: unknown solutions
« Reply #3 on: November 26, 2008, 08:32:36 AM »
You are right, there is no one direct method. I did read the original solution wrong. My bad

But I am sticking to my guns, as you can still use this method if you use one other compound as well (i.e. mix two with your starting solution). At first, you will make an insoluble salt in both, but the addition of one of the other compounds will force one of the equilibrium in the opposite direction, making the solution back to soluble!* :)


But using the fact that one is acidic and one is not, would be easier, I agree.

*edit*
In theory. It will be very tricky, and very concentration dependent! But I am still right! heh :)


« Last Edit: November 26, 2008, 11:47:35 AM by enahs »

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