Unformatted text preview: x 10‐37 FeS 6.0 x 10‐19 PbS 3.0 x 10‐28 MnS 3.0 x 10‐14 NiS 1.1 x 10‐21 SnS 1.0 x 10‐26 ZnS 2.0 x 10‐25 In the laboratory the following experimental conditions were observed: [M2+] = 0.01 M, [H2S] = 0.10 M, [HNO3] = 0.3 M. Which of the following metal ions from the chart will precipitate under these conditions? 78. At what pH will each of the nine sulfides begin to precipitate? 79. Notice that CdS is not a part of the Group II or Group III analysis. If we were to include Cd2+ in the qualitative scheme in the laboratory which group would it be included in? Give a valid reason to support your answer. 80. A solution containing Al3+, Cr3+, and Fe3+ was treated with NH3 to precipitate out Al(OH)3, Cr(OH)3, and Fe(OH)3. The solids were treated with NaOH and H2O2 which dissolved Al(OH)3 and Cr(OH)3 and left Fe(OH)3 as a solid. What chemical principle is responsible for this difference in solubility? 81. How would each of the following reagents affect the solubility of Fe(OH)3 in...
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- Spring '06