Could you please explain on a particle basis how the addition of a solute affects the boiling point and the freezing point and the vapor pressure of the solvent?

Answer 1

A solute adds particles to a solution, such as:

NaCl-> Na+ + Cl- This puts 2 particles in the solution for every 1 formula unit of table salt. Any particle that gets added to a liquid interferes with the liquids ability to form crystals (ice), it interferes with the liquids ability to break surface tension ( boiling), and since less liquid molecules can escape there is less vapor pressure.

Addition of a solute means:

To freeze the solution you would have to slow the molecules down more than normal to encourage crystal growth, so the temp must be lowered.

To boil the solution you would have to speed the molecules up more than normal to encourage the molecules to leave the liquid, so the temp must be increased.

To increase the vapor pressure of the solvent has the same explanation as boiling.

Answer 2

When a solute is added to a solvent, it increases the boiling point and the freezing point of the solution due to the presence of additional particles that disrupt the solvent's normal vapor pressure. This disruption occurs because the solute particles reduce the ability of the solvent particles to escape into the vapor phase, increasing the boiling point and lowering the freezing point. Additionally, the presence of solute particles also lowers the vapor pressure of the solvent because fewer solvent particles are able to vaporize at a given temperature.