When 1 mol of a nonvolatile nonelectrolyte is dissolved in 3 mol of a solvent,the vapor pressure of the solution compared with that of the pure solvent is
A)1/4.
B)4/5.
C)1/2.
D)1/5.
E)3/4.

Question

Quizplus · Accepted Answer

The vapor pressure of a solution is directly proportional to the mole fraction of the solvent according to Raoult's law. Here, the mole fraction of the solvent is 3/(1+3) = 3/4. Therefore, the vapor pressure of the solution is 3/4 that of the pure solvent.

When 1 Mol of a Nonvolatile Nonelectrolyte Is Dissolved in 3