Answer:

[tex]\frac{P_{solution}}{P_{solvent}^{vap}} =0.75[/tex]

Explanation:

Hello there!

In this case, since the solvation of a nonvolatile-nondissociating solute in a volatile solvent is modelled via the Raoult’s law:

[tex]P_{solution}=x_{solvent}P_{solvent}^{vap}[/tex]

Thus, we can calculate the ratio of the vapor pressure of the solution to that of the pure solvent, mole fraction, as shown below:

[tex]x_{solvent}=\frac{P_{solution}}{P_{solvent}^{vap}} =\frac{n_{solvent}}{n_{solute}+n_{solvent}}[/tex]

Thus, we plug in the moles of solvent and solute to obtain:

[tex]\frac{P_{solution}}{P_{solvent}^{vap}} =\frac{3}{3+1}\\\\ \frac{P_{solution}}{P_{solvent}^{vap}} =0.75[/tex]

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