A solution contains a mixture of pentane and hexane at room temperature. The solution has a vapor pressure of 270 torr . Pure pentane and hexane have vapor pressures of 425 torr and 151 torr, respectively, at room temperature.

This is an incomplete question, here is a complete question.

A solution contains a mixture of pentane and hexane at room temperature. The solution has a vapor pressure of 270 torr . Pure pentane and hexane have vapor pressures of 425 torr and 151 torr, respectively, at room temperature.

What is the mole fraction of hexane?

Answer : The mole fraction of hexane is, 0.566

Explanation :

According to Raoult's law,

where,

= total vapor pressure = 270 torr

= vapor pressure of pure pentane = 425 torr

= vapor pressure of pure hexane= 151 torr

= mole fraction of hexane = ?

= mole fraction of pentane

Now  put all the given values in the above formula, we get:

Thus, the mole fraction of hexane is, 0.566