Question

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 ______.

Options

• 0.25

• 0.50

• 0.75

• 0.90

Answer 1

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 0.25.

Explanation:

`(0.80 - 0.6)/0.80` = x_B;

x_B = 0.25