Vapor Pressure Lowering


Adding non-volatile solute to volatile solvent lowers the solvent’s vapor pressure. For example, water normally boils at 100 degrees C (212 F) but if you add something like salt to the solution, it decreases the vapor pressure of the solution.

  • The water will only boil if it’s vapor pressure is equal to atmospheric pressure. Thus you would need to heat the water to a higher temperature.
  • The vapor pressure lowering is a colligative property. Colligative property refers to the ratio of solute particles to solvent, and not the identity of the solute (identity which means the type of solute).

2 thoughts on “Vapor Pressure Lowering

  1. I’m a French student at Science University and It was quite difficult for me to understand colligative property before I discover your website. 🙂 Thank you for your clear explanations and your nice illustrations !

    1. Meilin, I’m glad you found this website helpful. Illustration is a very powerful tool for studying. Thank you again for your feedback and please support us by helping to spread the word!

Leave a Reply

Your email address will not be published.