Another important class of solutions consists of solids dissolved in
liquid, for example, sodium chloride, glucose, urea and cane sugar in
water and iodine and sulphur dissolved in carbon disulphide Some
physical properties of these solutions are quite different from those of
pure solvents For example, vapour pressure Liquids at a given
temperature 
vapourise 
and 
under
equilibrium conditions the pressure exerted
by the vapours of the liquid over the liquid
phase is called vapour pressure [Fig