how does adding a solute to a solvent affect its vapor pressure
Report Abuse. Adding a solute decreases the vapor pressure of the solution, decreases the freezing point (freezing point depression), and raises the boiling point (boiling point elevation) These are all called colligative properties.Source(s): AP Chemistry.WeMillSoOddly Â· 5 years ago.Thumbs up.dding a solute decreases the vapor pressure of the solution, decreases the freezing point (freezing point depression), and raises the boiling point (boiling point elevation) These are all called colligative properties. Source(s): AP Chemistry. WeMillSoOddly Â· 5 years ago. Thumbs up.