Test for anions in solution Organic Chemistry II

Test for anions in
solution



Organic Chemistry II (Liberty
University)




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, Anionic analysis can be conducted through three main methods: Bunsen, Gilreath, and
Vogel. The Bunsen method classifies anions based on the solubility properties of silver and
barium salts, color, solubility of alkali salts, and ease of volatilization. The Gilreath method
categorizes anions according to the solubility of calcium, barium, cadmium, and silver salts.
Vogel's approach involves identifying anions that evaporate when treated with acids and
analyzing their reactions in solution.


Typically, the Vogel method is used for anionic analysis. Anions are commonly divided into
three primary groups:


a. Sulfate Group: SO4^2-, SO3^2-, PO4^3-, Cr2O4^2-, BO2^-, CO3^2-, C2O4^2-, AsO4^-


b. Halide Group: Cl-, Br-, I-, S^2-


c. Nitrate Group: NO3-, NO2-, C2H3O2-


Testing for anions in solution:


1. Sulfate Test: Barium salts such as BaSO4, BaSO3, Ba2(PO4)3, BaCr2O4, Ba(BO2)2, BaCO3,
BaC2O4, Ba3(AsO4)2 are insoluble in water under alkaline conditions, while other barium
anion salts dissolve easily. The sulfate group can be separated and identified by adding a
BaCl2 reagent. Except for barium chromate, which is yellow, the other barium salts are
white.
2. Test for Reducing Agents




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