======Tollen's Test Silver Mirror======


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**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
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**Alternative titles:** Identification of Aldehydes
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====Summary====                   
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====Procedure====  
  - Add 5 mL of 10% silver nitrate solution to a clean flask.  
  - Add 1 mL of 10% sodium hydroxide solution.  
  - Add concentrated ammonia drop by drop until the brown silver oxide just dissolves, leaving a clear or slightly dark solution.  
  - Introduce 7 mL of 1% glucose solution and swirl gently.  
  - Within minutes, a silver mirror will form on the inner walls of the flask.



====Links==== 
Demonstration of Tollens' Reagent - Rugby School Chemistry: 
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Tollens Test - Silver mirror Reaction - MrGrodskiChemistry: 
{{youtube>B3uvzBb4zrQ?}}\\

📄 Identification of Aldehydes – Tollen's Test - University of Colorado Boulder: [[https://www.colorado.edu/lab/lecture-demo-manual/o630-identification-aldehydes-tollens-test]]\\

📄 Tollens' Test for Aldehydes - University of Washington: [[https://chem.washington.edu/lecture-demos/tollens-test-aldehydes]]\\

====Variations====
  * Use different aldehydes instead of glucose to compare reactivity.  
  * Perform the test in a test tube instead of a flask for quicker observation.  
  * Demonstrate with reducing sugars (such as fructose or lactose) to show biological relevance.



====Safety Precautions====
  * Wear gloves to prevent skin staining from silver nitrate.  
  * Avoid contact of silver nitrate with skin or clothing, as it leaves permanent stains.  
  * Work in a well-ventilated area to minimize inhalation of ammonia vapors.  
  * Use concentrated nitric acid carefully to remove the silver mirror after the experiment.  
  * Dispose of silver waste according to local hazardous waste protocols.




====Questions to Consider====
  * Why does Tollen’s reagent react with aldehydes but not most ketones? (Aldehydes are more easily oxidized than ketones.)  
  * What role does ammonia play in preparing Tollen’s reagent? (It dissolves the silver oxide, forming the reactive diamminesilver(I) complex.)  
  * Could this test distinguish between glucose and sucrose? (Yes, glucose is a reducing sugar and gives a positive test, while sucrose does not.)