the elevation in boiling point is explained as a colligative property of every solutions.but,for solutions showing positive deviation from raoult's law,the intermolecular attractive forces between solute-solvent molecules are weaker than those between solute- solute and solvent-solvent molecules.this can only result in a lowering of boiling point.how is this possible?
the elevation in boiling point is explained as a colligative property of every solutions.but,for solutions showing positive deviation from raoult's law,the intermolecular attractive forces between solute-solvent molecules are weaker than those between solute- solute and solvent-solvent molecules.this can only result in a lowering of boiling point.how is this possible?
If in a binary solution (showing positive deviation ) of two components A and B, the interaction between unlike components A-B is weaker than the interaction between the like components A-A and B-B, then it means that in such solutions molecules of A (or B) will find it easier to escape in the state A-B, than when they are in their pure states (A-A or B-B). It means that molecules of A (or B) will find it easier to escape from the A-B form.
This will result in having greater vapour pressure of each component of the solution than expected on the Basis of Raoult's law, and hence the total vapor pressure will also be higher than in the case of ideal solution.
For a positive deviation, the vapour pressure for a given mixture is greater than would be expected (and therefore the boiling point is lower). Because the vapour pressure is higher, the liquid is evaporating more easily than would be expected.
If in a binary solution (showing positive deviation ) of two components A and B, the interaction between unlike components A-B is weaker than the interaction between the like components A-A and B-B, then it means that in such solutions molecules of A (or B) will find it easier to escape in the state A-B, than when they are in their pure states (A-A or B-B). It means that molecules of A (or B) will find it easier to escape from the A-B form.
This will result in having greater vapour pressure of each component of the solution than expected on the Basis of Raoult's law, and hence the total vapor pressure will also be higher than in the case of ideal solution.
For a positive deviation, the vapour pressure for a given mixture is greater than would be expected (and therefore the boiling point is lower). Because the vapour pressure is higher, the liquid is evaporating more easily than would be expected.
