Unformatted text preview: 4 to each solution. The Pb 2+ would form a white precipitate, while there would not be a precipitate with the Fe 3+. Cr 3+ , Hg 2+ Again the simplest test would be the color of the solution . Cr 3+ solutions are blue-black while those of Hg 2+ are colorless. Addition of excess NaOH causes Cr 3+ solutions to precipitate and the precipitate redissolve while Hg 2+ would lead to a yellow-orange precipitate. Cl 1-, NO 3 1-The easiest test here would be to add AgNO 3 . This would lead to the formation of a white precipitate by the chloride ion and no reaction form the NO31-. Add FeSO 4 and H 2 SO 4 and look for a brown ring at the interface with NO 3 1-and no ring with Cl 1-. Note: since these are ions in aqueous solution, treatment with concentrated sulfuric acid will not work, as that test needs to be run on solid samples of the unknowns....
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- Spring '08
- Chemistry, Sulfuric acid, white precipitate