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Chemical Identification for Competition

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sammysue07:
hm... i will check out the attachment....

i printed it and wil read it soon

Garneck:
If you have access to water and you can dissolve those compunds, then:
1. Mg(OH)2 and CaCO3 won't dissolve or at least they won't dissolve well.
2. My choice would be AgNO3, because then you can identify the compund by the Ag+ + anion precipitate (only Al(NO3)3 won't give you any reaction)
3. One problem: I have no idea how you will tell the difference between amonium chloride and zinc chloride.

Donaldson Tan:

--- Quote from: Garneck on April 07, 2005, 01:53:31 AM ---3. One problem: I have no idea how you will tell the difference between amonium chloride and zinc chloride.

--- End quote ---

Once you have identified sodium bicarbonate, you can use it as a source of OH- to precipitate Zinc. Ammonium chloride will give you negative observation

AWK:
1. Prepare water solutions from your samples. Two compounds are insoluble. They can be identified by HCl (bubles of CO2 for CaCO3)
2.  Phenolphtalein test - you will identify KOH
3. To samples of other 7 solutions add AgNO3 - you can obtain 6 precipitates from which 3 (AgI, Ag2S and Ag3PO4) can be identified by colour , other 3 will be white, though they can change color slowly.
4. To the samples of solutions that produce white precipitates with AgNO3 add dropwise NaOH.  Only ZnCl2 will form white precipitate. Zn(OH)2 will dissolve in excess of NaOH. Treat samples of NaHCO3 or NH4Cl with HCl - CO2 bubbles will identify NaHCO3
5. The last solution should contain Al(NO3)3. Check it using NaOH (dropwise).

sammysue07:

--- Quote from: AWK on April 07, 2005, 04:43:35 AM ---1. Prepare water solutions from your samples. Two compounds are insoluble. They can be identified by HCl (bubles of CO2 for CaCO3)
2.  Phenolphtalein test - you will identify KOH
3. To samples of other 7 solutions add AgNO3 - you can obtain 6 precipitates from which 3 (AgI, Ag2S and Ag3PO4) can be identified by colour , other 3 will be white, though they can change color slowly.
4. To the samples of solutions that produce white precipitates with AgNO3 add dropwise NaOH.  Only ZnCl2 will form white precipitate. Zn(OH)2 will dissolve in excess of NaOH. Treat samples of NaHCO3 or NH4Cl with HCl - CO2 bubbles will identify NaHCO3
5. The last solution should contain Al(NO3)3. Check it using NaOH (dropwise).

--- End quote ---

Thanks for all of the information, but we can only use one of the solutions.

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