======Sublimation of Naphthalene======


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**Alternative titles:** Purification of Solids by Sublimation
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====Summary====                   
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====Procedure====  
  - Place about 1 g of impure naphthalene mixed with sand into a 200 ml beaker.  
  - Cover the beaker with a round-bottomed flask filled with cold water or ice.  
  - Heat the beaker gently on a hotplate or with a low flame.  
  - Observe naphthalene vapors rising and depositing as pure crystals on the cold flask and beaker walls.  
  - Scrape off the deposited naphthalene crystals.  
  - Collect the purified sample in a small flask, weigh it, and determine its melting point to confirm purity.



====Links==== 
Sublimation of Mothballs - Science Made Easy: 
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Separate Naphthalene from the given mixture of sand and naphthalene - Chemistry Plus: 
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📄 Sublimation - uomustansiriyah.edu.iq: [[https://uomustansiriyah.edu.iq/media/lectures/6/6_2021_07_16!08_20_55_PM.pdf]]\\

====Variations====
  * Try using a condenser tube cooled with running water instead of an ice-filled flask.  
  * Compare sublimation with simple filtration to highlight differences in purification techniques.



====Safety Precautions====
  * Wear safety goggles, gloves, and a lab coat.  
  * Naphthalene is toxic if inhaled or ingested; avoid breathing vapors.  
  * Perform the experiment in a well-ventilated area or fume hood.  
  * Handle hot glassware with care to prevent burns.  
  * Dispose of waste materials safely according to laboratory guidelines.




====Questions to Consider====
  * Define sublimation and triple point. (Sublimation: solid to gas phase transition without liquid phase. Triple point: the unique temperature and pressure at which solid, liquid, and gas coexist.)  
  * What is the difference between sublimation and desublimation? (Sublimation: solid to gas; desublimation: gas to solid.)  
  * Which compounds can be purified by sublimation? (Examples: camphor, benzoic acid, naphthalene, salicylic acid, quinine.)  
  * Why is ice used in the sublimation experiment? (It cools the vapor, allowing it to redeposit as pure crystals.)  
  * How can melting point determination confirm the purity of the sublimed product? (A pure substance has a sharp melting point close to its literature value, while impurities lower and broaden the melting point range.)