2.48: Describe Tests for these Anions: Cl-, Br- and I- Using Acidified Silver Nitrate Solution, SO42- Using Acidified Barium Chloride Solution, CO32- Using Hydrochloric Acid and Identifying the Gas Evolved

ANIONS: Negatively charged ion

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TEST FOR Cl-, Br- and I- :

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TEST FOR CHLORIDE, BROMIDE AND IODIDE
Diagram showing the Test for Cl-, Br- and I-
METHOD: Add a small volume of Dilute Nitric Acid to react and remove Carbonate ions from sample solution Add a few drops of Silver Nitrate Solution Colour of precipitate is observed and recorded
RESULT AND EQUATION:
HALIDE ION PRESENT	COLOUR OF PRECIPITATE	EQUATION
CHLORIDE ION  Cl-	White Precipitate	Ag+    +    Cl-    →    AgCl
BROMIDE ION    Br-	Cream Precipitate	Ag+    +    Br-    →    AgNr
IODIDE ION         I-	Yellow Precipitate	Ag+    +    I-    →    Agl

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TEST FOR SO4 :

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TEST FOR SULFATE IONS

Diagram showing the Test for Sulfate Ions

METHOD: Add a small volume of Dilute Hydrochloric acid to react and remove Carbonate ions Add a few drops of Barium Chloride Solution Colour of precipitate is observed and recorded

RESULT: If Sulfate ions are present, White precipitate will form (Barium Sulfate)

EQUATION:   Ba2+ (aq)      +         SO4-  (aq)      →         BaSO4 (s)

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TEST FOR CO3 :

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TEST FOR CARBONATE IONS

Diagram showing the Test for Carbonate Ions

METHOD: Add Dilute Hydrochloric acid Gas produced is bubbled into limewater Colour of precipitate is observed and recorded

RESULT: If Carbonate ions are present, limewater will turn milky

EQUATION:   CO32- (aq)      +         2H+  (aq)      →         CO2 (g)         +         H2O  (l)