QS Study

Characteristics of unsaturated vapour pressure

An unsaturated solution is when the solute can’t dissolve in the solvent. For example, if you have a glass of water, and you pour something like vegetable oil into it, it will not dissolve. So that makes the solution unsaturated. The maximum limit of water vapour that a given quantity of air can hold at a particular temperature is termed as saturated vapour. In such a case, relative humidity will be 100 percent. For all other cases, where the maximum limit of vapour is not reached, the vapour thus formed is termed as unsaturated vapour.

  • A vapour in a dosed space is said to be unsaturated at a given temperature if the pressure is less than the saturated vapour pressure at that temperature.
  • It can be created in a closed or open space.
  • If there exists some vapour in a confuted space but there is no liquid in that space, then that vapour can either be unsaturated or just saturated. If some vapour becomes liquid due to the decrease of the volume of that space, then that vapour is just saturated, otherwise unsaturated.
  • Unsaturated vapour follows Boyle’s law and Charles’s law.
  • By decreasing temperature, a fixed amount of unsaturated vapour can be made saturated.
  • Unsaturated vapour does not remain in equilibrium with its liquid.