Umer Farooq Dogar09040606-028Physical chemistryCourse code:272Submitted To: Sir Munir AwanB.S Botany 3rd semester
Determination of elevation of boiling point There are two main methods to determine the boiling point1. The Landberger’s method:2. Cottrell’s method:
The landberger’s method The method which is used is consisted of four major parts.i. Boiling flask is used to boil the pure solvent and get its vapours.ii. An inner boiling tube whose middle portion is blown into a bulb and has a hole in the side.iii. Beckmann thermometer which can read upto 1/100th of a degree.iv. Hot vapour jacket surrounding the inner glass tube
Landberger’s method: Take 10 ml of the pure solvent in the inner boiling tube. The solvent is boiled in the flask and vapours are transferred to inner tube. The latent heat of condension of the vapours raises the tempeture in the inner tube upto its boiling point. The boiling point of the pure solvent is noted with the help of Beckmann’s thermometer.
Landberger’s method Let this temperature be T. An accurate weight quantity of solute is added in the inner tube and again the boiling is noted as don previously. The volume of solution the at the stage of its boiling is measured. The density of this solution is determine later on
Landberger’s method From the density and the volume , the mass of the solution in the inner tube is calculated. From the mass of solute, mass of the solvent and the elevation of the boiling point, we can calculate the molar mass of the solute