Addition of salt modifies the properties of water. Slide 12 of 13 Addition of salt modifies the properties of water. Pure water freezes at 0oC. Adding salt increasingly lowers the freezing point because salt ions interfere with the formation of the hexagonal structure of ice. Density of water increases as salinity increases.
Vapor pressure is the pressure exerted by the gaseous phase on the liquid phase of a material.
It is proportional to the amount of material in the gaseous phase. Vapor pressure decreases as salinity increases because salt ions reduce the evaporation of water molecules.