Mintu Philip Chemistry 127 Lab Professor Dr. Myungshim Kang March 23, 2018 Lab Report #6 – The Chemistry and Qualitative Analysis of Cation: Group II Known Partner: Lena Ahmed Locker#31
Purpose: Develop the chemistry of the selected group II cations (Bi, Cd, Cu and Sn Cl 16 ions). Use this chemistry to establish a procedure for verifying qualitatively the presence of these selected cati-ons. Apply this procedure to identify and confirm the presence of unknown cations in a solution. Materials: Gloves, goggles, graduated cylinder, dropper, small test tubes, centrifuging device, rubber bands, large beaker, hot plate, square test tube holder plate, large test tube, short range Alkacid test pa-per, wide range Alkacid paper, HCl, distilled water, thiocetamide, NH 3 , CH 3 CS NH 2, KOH , HNO 3 . Procedure: - Obtain unknown solution from Professor and test pH with short range Alkacid paper. It should be light green. - Then add 10 drops of 1 M thiocetamide CH 3 CS NH 2, . - Heat 10 minutes in boiling water, cool, add 1 drop of 0.5 M. NH 3 . - Centrifuge for 2 minutes - Add 5 drops of 1M thiocetamide, heat 2 minutes in boiling water bath, cool, add 1 drop of 0.5M NH 3 . - Centrifuge for 2 minutes. Discard supernatant liquid. And add 1 mL of 0.1M CH3CSNH2. - Centrifuge for 2 minutes. Discard supernatant liquid, and you are left with the residue. - Add 20 drops of 3M KOH, then add 1 drop of 1M thiocetamide. Heat for 2 minutes in boiling water bath. - Then centrifuge for 2 minutes. - The supernatant liquid is to be separated and mixed with 6M HCl to turn acidic. Then add 5 drops of 1M thiocetamide and heat for 2 minutes in boiling water. Record observations. - With the left over residue we add 1 mL of H 2 O, and centrifuge for 2 minutes. The supernatant liquid is to be discarded in this step. - With the residue you record observations and then add 10 drops of H 2 O. - Then add 2 drops of 6M HCl, and heat for 2 minutes in boiling water, then centrifuge for 2 minutes. - The supernatant liquid of this step is to be tested and adjusted to be basic. We separate the supernatant from the residue and add drop wise 6M NH 3 until the orange alkacid paper turns blue.
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