KingAbdul-AzizUniversity-RABIGH.doc

King Abdul-Aziz University- RABIGH Faculty of Science Department of Chemistry Detection of Miscellaneous group Sulphates (SO4--) Solubility in water: Most sulphates dissolve in water except those of some divalent metals e.g. mercuric, lead, calcium, barium, and strontium sulphate. Chemical properties: A) Add barium chloride solution to the salt solution; observe the formation of (white ppt) of barium sulphate which is not dissolved in excess of barium chloride, dilute mineral acids and conc. acids. Na2SO4 + BaCl2 = ↓ BaSO4 + 2NaCl Sodium sulphate +Barium chloride = Barium sulphate + Sodium chloride Confirmatory test: 1) Add lead acetate solution to the salt solution; observe the formation of (white ppt) of lead sulphate divide the ppt into two tubes. a) White ppt + ammonium acetate solution → white ppt dissolves b) White ppt + Sodium hydroxide → white ppt dissolves Na2SO4 + Pb (CH3COO)2 = ↓ PbSO4 + 2CH3COONa Sodium sulphate + Lead acetate = Lead sulphate + Sodium acetate 2) Add silver nitrate solution to the salt solution (white ppt) of silver sulphate will be formed. Na2SO4 + 2AgNO3 = ↓ Ag2SO4 + 2NaNO3 Sodium sulphate + silver nitrate = silver sulphate + Sodium nitrate King Abdul-Aziz University- RABIGH Faculty of Science Department of Chemistry Detection of Miscellaneous group Detection of Sulphates (SO4--) Physical properties: 1- Salt color: 2- Crystalline shape: 3- Solubility in water and its effects on litmus paper: Chemical properties: Conclusions Observations Experiments ↓ BaSO4)) Formation of (white ppt) of barium sulphate which is not dissolved in dilute mineral acids and conc. acids. A) Salt solution+ Barium chloride solution Na2SO4 + BaCl2