Elevation of boiling point HD

Useful for CBSE, ICSE, NCERT & International Students Grade 12 Subject: Chemistry Lesson :The p-Block Elements Topic: Elevation of boiling point The vapour pressure of a liquid increases with increase of temperature. It boils at the temperature at which its vapour pressure is equal to the atmospheric pressure. For example, water boils at 373.15 K (100° C) because at this temperature the vapour pressure of water is 1.013 bar (1 atmosphere). We have also learnt in the last section that vapour pressure of the solvent decreases in the presence of non-volatile solute. For example, the vapour pressure of an aqueous solution of sucrose is less than 1.013 bar at 373.15 K. In order to make this solution boil, its vapour pressure must be increased to 1.013 bar by raising the temperature above the boiling temperature of the pure solvent (water). Thus, the boiling point of a solution is always higher than that of the boiling point of the pure solvent in which the solution is prepared. Similar to lowering of vapour pressure, the elevation of boiling point also depends on the number of solute molecules rather than their nature. A solution of 1 mol of sucrose in 1000 g of water boils at 373.52 K at one atmospheric pressure. Visit www.oztern.com to find personalized test preparation solutions for Pre Medical - AIPMT, AIIMS, JIPMER, State, Pre Engineering - IIT JEE, JEE MAIN, BITSAT, State and Foundations - Class 6 to 10.