======Limiting Reactant======


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**Alternative titles:** Limiting Reagents, Limiting Reagents Vinegar and Baking Soda
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====Summary====                   
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====Procedure====  
  - Fill five Erlenmeyer flasks with 70 mL of vinegar each.  
  - Measure out 2 g, 4 g, 6 g, 8 g, and 10 g of baking soda into separate balloons.  
  - Carefully attach each balloon to a flask so that the baking soda does not spill into the vinegar.  
  - Raise the balloons one at a time to drop the baking soda into the vinegar.  
  - Observe the size of the balloon inflation and whether any solid remains at the bottom of the flask.  
  - Add bromothymol blue to each flask after the reaction:  
      - Yellow solution = vinegar in excess (acidic).  
      - Blue solution = baking soda in excess (basic).  
      - Green solution = near neutral, close to stoichiometric balance.  
  - Confirm predictions by adding extra vinegar to the basic flask and extra baking soda to the acidic flask.  
  - Guide students to calculate the limiting reagent, the excess reagent, and the amounts of products for each flask.



====Links==== 
Chemical Reactions: Limiting Reagents - Science World: 
{{youtube>ffQo4ceL4lQ?}}\\

Limiting Reactant Demonstration - cheminstrinaminute: 
{{youtube>nQ-uy2l5zCw?}}\\

📄 Limiting and excess reagents - University of Waterloo: [[https://uwaterloo.ca/chem13-news-magazine/december-2015-january-2016/activities/sharing-chemistry-community-limiting-and-excess-reagents]]\\


====Variations====
  * Use a gas syringe to measure the volume of carbon dioxide more precisely instead of balloon size.



====Safety Precautions====
  * Wear safety goggles and gloves when handling vinegar and indicator.  
  * Avoid ingestion, inhalation, or skin contact with bromothymol blue.




====Questions to Consider====
  * How does the size of the balloon indicate which reagent is limiting?  
  * Why does leftover baking soda or vinegar signal the presence of an excess reagent?  
  * What do the color changes with bromothymol blue reveal about the solution?  
  * How do stoichiometric calculations confirm the experimental results?