Qualitative Analysis of Common Anions

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Title: Experiment 1: Qualitative Analysis of Common Anions Aims To qualitatively analysis common anions of SO42- , PO43-, CO32-, S2-, I-, Br-, Cl- and NO3-. Procedure Please refer to laboratory manual page 14 to 22. Results Procedure Number and Ion | Test Reagent or Technique | Evidence of Chemical Change | Chemical(s) Responsible for Observation | Equation(s) for Observed Reaction | * | Addition of NH3 Addition of Ba(NO3)2 | White precipitate | BaSO4(s), BaCO3(s), Ba3(PO4)2(s) | SO42-(aq) + Ba(NO3)2(aq) BaSO4(s)CO32-(aq) + Ba(NO3)2(aq) BaCO3(s)3(PO4)3-(aq) + 3Ba(NO3)2(aq) Ba3(PO4)2(s) | * | Separation of SO42-, PO43- & CO32- by centrifugation. | Colourless solution and white precipitate | BaSO4(s), BaCO3(s), Ba3(PO4)2(s) | - | * SO42- | Addition of HNO3Centrifugation | Colourless solution and white precipitate | BaSO4(s) | Ba2+(aq) + SO42-(aq) BaSO4(aq) | * PO43- | Addition of (NH4)6Mo7O24 Put in warm water | Yellow precipitate | (NH4)3PO4(MoO4)12(s) | Ba3(PO4)2(s) + 2H+(aq) 3Ba2+(aq) + 2HPO42- (aq)HPO42-(aq) + 12(NH4)2MoO4(aq) + 23H+(aq) (NH4)3PO4(MoO4)12(s) + 21NH4+(aq) + 12H2O(l) | * CO32- | Centrifuge mixtureAddition of HNO3Immediately insert a stirring rod | White precipitate | CaCO3(s) | CO3 2-(aq) + 2H+(aq) H2O(l) + CO2(g) CO3 2-(aq) + 2OH-(aq) CO3 2-(aq) + H2O(l)CO3 2-(aq) + Ca2+(aq) CaCO3(s) | * S2- | Addition of HNO3Addition of Cu(NO3)2Centrifugation | White precipitate and green solution | CuS (s) | Cu2+ (aq) + S2- (aq) CuS (s) | * I- | Addition of Fe(NO3)3Addition of toluene | Formation of purple layer | I2(toluene) | 2Fe3+ (aq) + 2I- (aq) 2Fe2+(aq) + I2(toluene) | * Br- | Addition of tolueneAddition of HNO3Addition of KMnO4 | Formation of brown layer | 5Br2(toluene) | 2MnO4- (aq) +10Br-(aq) +16H+(aq) 2Mn2+ (aq) + 5Br2(toluene) + 8H2O(l) | * Cl- | Addition of AgNO3 |

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