======Vanadium Oxidation States======


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**Alternative titles:** Colors of Vanadium
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====Summary====                   
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====Procedure====  
  - Prepare sodium vanadate by heating vanadium pentoxide and sodium carbonate in water until the solution turns green.  
  - Add concentrated sulfuric acid to the sodium vanadate solution to form yellow vanadyl sulfate (V⁵⁺ state).  
  - Transfer the solution to a flask and heat gently while adding zinc granules.  
  - Observe as the solution changes colors: yellow (V⁵⁺), green (V⁴⁺), blue (V³⁺), dark-green, and finally purple (V²⁺).  
  - Pour samples into separate beakers at each stage to preserve the different colors.  
  - To reverse the sequence, add potassium permanganate to re-oxidize the solution, changing the colors back through green, blue, and yellow, then to orange and red.



====Links==== 
Oxidation States of Vanadium - Rugby School Chemistry: 
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📄 Vanadium Oxidation States Experiment - ChemTalk: [[https://chemistrytalk.org/vanadium-oxidation-states-experiment/]]\\

====Variations====
  * Explore the stability of each color by leaving the solutions exposed to air for different amounts of time.



====Safety Precautions====
  * Wear safety goggles, gloves, and a lab coat at all times.  
  * Vanadium compounds are toxic—avoid inhaling dust or vapors and prevent skin contact.  
  * Handle sulfuric acid with care; it is highly corrosive.  
  * Potassium permanganate is a strong oxidizer—do not mix with flammable or organic materials.  
  * Work in a well-ventilated area or fume hood when handling powdered chemicals.  
  * Dispose of vanadium compounds properly as heavy metal waste; do not pour large amounts down the drain.




====Questions to Consider====
  * Why do vanadium compounds display so many different colors? (Because d-orbital electrons absorb light at different wavelengths depending on the oxidation state.)  
  * Why is zinc used in this experiment? (It acts as a reducing agent, lowering the oxidation state of vanadium step by step.)  
  * Why does the purple V²⁺ state fade quickly in air? (It is unstable and gets oxidized back to V³⁺ by oxygen.)  
  * What is the role of potassium permanganate? (It is a strong oxidizing agent that reverses the reduction and restores higher oxidation states of vanadium.)