The vapour pressure of a solvent A is 0.80 atm. When a non-volatile substance B is added to this solvent its vapour pressure drops to 0.6 atm. the mole fraction of B in the solution is [MP PMT 2000]

(1) 0.25

(2) 0.50

(3) 0.75

(4) 0.90

Concept Videos :-

#3 | Introduction to Colligative Properties
#4 | Relative Lowering Introduction to Colligative Properties

Concept Questions :-

Relative Lowering of Vapour Pressure/ Vapour Pressure

(1) ΔP/P0=XB or XB=0.2/0.8=0.25   

Difficulty Level:

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