The formation of a brown solution. Color disappears with alkaloid's solution in extremely low concentration
name: The formation of the complex salt of bismuth and its reaction with alkaloids
Make Dragendorff's reagent from Bismuth Nitrate
The Home Scientist 022 - Testing for Alkaloids with Dragendorff Reagent
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Bi(NO3)3 + 4 KI → K[BiI4] + 3 KNO3
- Pour 0.5 g of bismuth nitrate into an empty beaker. Add about 10 ml of distilled water. The mixture should be like a suspension.
- Add 10 ml of concentrated hydrochloric acid. Stir the resulting mixture.
- Pour 4 g of potassium iodide into another beaker, add a little water and stir until KI is completely dissolved.
- Mix the two solutions.
- Observe the formation of a dark orange solution.
Bismuth nitrate is the most commercially available reagent of Bi. It reacts with potassium iodide in an acidic solution and forms potassium bismuth iodide (typically represented as K[BiI4] ) solution. The orange mixture prepared in this experiment is the Dragendorff’s reagent used for detection of alkaloids in a test solution.