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Sol ubi l i t y i n Ammoni a
Add 10 drops of 3 M NH3 to the solids that did not dissolve in hot water in step 6. Record your observations in
Data Table B (color change? redissolve? etc.).
Perform a confirmatory test for any solution in step 9 for which solid dissolves. Confirmatory Test: Add 5 drops
of 0.2 M KI to the test tube. Enter your observations in Data Table A. The contents of this test tube may be
discarded into the waste.
Note : One partner should perform Part C while the other partner performs Part D simultaneously. This will
www.webassig n.net/ebooks/wsug encheml1/lab_5/manual.html 4/6 4/15/13 Lab 5 - Qualitative Analysis allow comparison between a solution that is k nown to contain Ag1+, Pb2+ and Hg2 2+ (Part C) with one that
may or may not contain all three (Part D). Be very careful with data collection since both partners will be
performing the same tests on different solutions. Part C: Developing a Separation Scheme for a Mixture of All Three Ions
Add 5 drops of each cation solution (Ag1+, Pb2+ and Hg2 2+) to a single test tube. This will simulate conditions
in an unknown mixture. Sol ubi l i t y i n HCl
Add a few drops of 3 M HCl. A precipitate will appear. Continue adding HCl until no more solid appears to be
forming. Centrifuge the sample.
Add another drop of HCl. If no precipitate forms, go to step 3. If more solid appears, add HCl until no more
forms. Centrifuge again, and add another drop of HCl. Continue this until no more solid forms, then go to step 3.
Record your observations in Data Table C1.
Decant the supernatant liquid into a clean test tube and perform a confirmatory test. Confirmatory Test: Add 5
drops of 0.2 M KI to the test tube. Record your observations in Data Table C2. The contents of this test tube
may be discarded into the waste.
Wash the solid with deionized water as you did in step 5 of Part B. Decant the washing liquid into the waste.
Washing the precipitate removes any soluble ions and prevents problems in future steps, such as false positives
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This document was uploaded on 01/22/2014.
- Spring '14