MEDIUMMCQ SINGLEJEE Mains ChemistryPhysical ChemistrySolutionsRelative lowering of vapour pressure
In three beakers labelled as (A), (B) and (C), 100 mL of water, 100 mL of 1M solution of glucose in water and 100 mL of 0.5 M solution of glucose in water are taken respectively and kept at same temperature. Which of the following statements is correct?
A.Vapour pressure in all the three beakers is same.
B.Vapour pressure of beaker B is highest.
C.Vapour pressure of beaker C is highest.
D.Vapour pressure of beaker B is lower than that of C✓ Correct
Explanation
Vapour pressure is a colligative property V.P.of solvent is inversely proportional to mole fraction of the solvent .Beaker B contains maximum number of moles of solute in it. The solute replaces the solvent molecules from the surface and decrease the vapour pressure of solution. Breaker B will have lowest V.P next will be the c and then A