Systematic Separation of Cations into Groups PDF
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This document outlines procedures for systematically separating cations into groups based on their chemical properties, including precipitation reactions and analysis. The document also contains a summary of results for identified cation groups, a helpful guide for laboratory experiments involving separation techniques.
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Systematic Separation of Cations into Groups Summary of Procedures Group I Cations (PbCl₂, AgCl, Hg₂Cl₂) Precipitation: Add 3F HCl to the original solution. Centrifuge. Separation of Lead Chloride: Heat the precipitate with water. Centrifuge. Group II-A Cations (HgS, PbS, Bi₂S₃, CuS...
Systematic Separation of Cations into Groups Summary of Procedures Group I Cations (PbCl₂, AgCl, Hg₂Cl₂) Precipitation: Add 3F HCl to the original solution. Centrifuge. Separation of Lead Chloride: Heat the precipitate with water. Centrifuge. Group II-A Cations (HgS, PbS, Bi₂S₃, CuS, CdS) Precipitation: Add HNO₃, NH₃, HCl, and thioacetamide. Centrifuge. Separation: Treat residue with KOH. Centrifuge. Group II-B Cations (As₂O₃, As₂S₃, Sb(OH)₄, Sb₂S₃, Sn(OH)₄, SnS₂) Analysis: Analyze centrifugate from Group II-A separation. Group III-A Cations (Al(OH)₃, CrO₄², Zn(NH₃)₄²⁺) Precipitation: Add NH₄Cl, NH₃, thioacetamide. Centrifuge. Analysis: ○ Residue (Al(OH)₃): Wash, add HCl, aluminon, NH₃. Red precipitate indicates Al. ○ Centrifugate (CrO₄², Zn(NH₃)₄²⁺): Add BaCl₂. Precipitate may be BaCrO₄ and BaSO₄. Add HCl, H₂O₂, filter paper. Blue color which fades indicates Cr. Add HAc, thioacetamide. White precipitate indicates Zn. Group III-B Cations (MnO(OH)₂, Fe(OH)₃, Co(OH)₃, Ni(OH)₂) Separation: Wash precipitate, dissolve in HCl, dilute. Analysis: Divide into four portions. ○ First portion: Add sodium bismuthate. Reddish-purple color indicates Mn. ○ Second portion: Add NH₄CNS. Red color indicates Fe. ○ Third portion: Add NaF, NH₄CNS. Green color at junction indicates Co. ○ Fourth portion: Add NaF, NH₃, dimethylglyoxime. Red precipitate indicates Ni. Group IV Cations (Ba³(PO₄)₂, Sr₃(PO₄)₂, Ca₃(PO₄)₂, MgNH₄PO₄) Precipitation: Add NH₄HPO₄, NH₃. Centrifuge. Group V Cations (Na⁺, K⁺, Li⁺, NH₄⁺) No precipitation: Remaining cations in solution. Summary of Results Group Cations I PbCl₂, AgCl, Hg₂Cl₂ II-A HgS, PbS, Bi₂S₃, CuS, CdS II-B As₂O₃, As₂S₃, Sb(OH)₄, Sb₂S₃, Sn(OH)₄, SnS₂ III-A Al(OH)₃, CrO₄², Zn(NH₃)₄²⁺ III-B MnO(OH)₂, Fe(OH)₃, Co(OH)₃, Ni(OH)₂ IV Ba³(PO₄)₂, Sr₃(PO₄)₂, Ca₃(PO₄)₂, MgNH₄PO₄ V Na⁺, K⁺, Li⁺, NH₄⁺
