Ferrous ammonium suifate

Ferrous ammonium suifate, Mohr s salt, FeS04 (NH4)2S04 6H2O—0.5N 196 g per liter. Ferrous sulfate, FeS04 7H2O—0.5N 80 g per liter add a few drops of H2SO4. 

In a smaii test tube, mix about 20 mg of a soiid or 1 drop of a iiquid unknown with 1.5 mL of freshly prepared 5% ferrous ammonium suifate soiution. Add 1 drop of 3 M sulfuric acid and 1 mL of 2 M potassium hydroxide in methanol. Stopper the tube immediately and shake it. A positive test is indicated by the blue precipitate turning rust-brown within 1 min. A slight darkening or greenish coloration of the blue precipitate is nof considered a positive test. 

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