1. CHM 101/102 Laboratory Manual Qualitative Analysis: Group I General Chemistry 101/102 Laboratory Manual University of North Carolina at Wilmington

2. CHM 101/102 Laboratory Manual Qualitative Analysis: Group I Purpose Purpose  To study the chemical properties of Ag +, Pb 2+, and Hg 2 2+ ions and the compounds they form.  Use the chemical properties of these ions to identify their presence in an unknown mixture. Safety Considerations Safety Considerations  Pb 2+ and Hg 2 2+ ions are very toxic.  Wash your hands thoroughly after this experiment.  Place all waste solids and solutions in the appropriately labeled containers in the hood.

3. CHM 101/102 Laboratory Manual Qualitative Analysis: Group I General Procedures General Procedures  Use clean glassware and deionized water to avoid contaminating your sample.  Distinguish between clear, cloudy, colored, and colorless in your descriptions. cloudy yellow clear yellow clear colorless white solid

4. CHM 101/102 Laboratory Manual Qualitative Analysis: Group I General Procedures General Procedures  Exercise caution when using the centrifuge. Use a counterbalance tube. sample counterbalance

5. CHM 101/102 Laboratory Manual Qualitative Analysis: Group I  Use a water bath to heat all mixtures. General Procedures General Procedures  Pay attention to whether you are to keep or discard the precipitate and/or supernatant. supernatant precipitate

6. CHM 101/102 Laboratory Manual Background Background  Ag +, Pb 2+, and Hg 2 2+ ions all form white precipitates with Cl - at room temperature. Qualitative Analysis: Group I 6 M HCl AgCl, PbCl 2, Hg 2 Cl 2

7. CHM 101/102 Laboratory Manual Background Background  PbCl 2 is insoluble in cold water but soluble in hot water. PbCl 2 can be separated from AgCl and Hg 2 Cl 2 by heating the mixture. Qualitative Analysis: Group I  Pb 2+ ions can be precipitated with K 2 CrO 4. PbCrO 4 is insoluble in hot and cold water. PbCrO 4

8. CHM 101/102 Laboratory Manual Background Background Qualitative Analysis: Group I  When NH 3 (aq) is added to a mixture of AgCl and Hg 2 Cl 2, the AgCl dissolves and a gray-black mixture of Hg and HgNH 2 Cl is formed.  Ag + ions can be precipitated as AgCl by the addition of HNO 3.

9. CHM 101/102 Laboratory Manual Qualitative Analysis: Group I