Question

At 20 degrees celcius the vapor pressure of toluene is 22 mmhg and that of benzene is 75 mmhg. Assume an ideal solution, equimolar in benzene and toluene. At 20 degrees celcius what is the mole fraction of benzene in the vapor in equilibrium with this solution?

If you use pv=nRt how would you find v and n. Or how do you solve this a different way

Answer 1

Note the correct spelling of celsius.
Equimolar means Xtol = Xben = 0.5

ptol = Xtol*Po toluene.
pben = Xben*P. benzene.
Ptotal = ptol + pben

Xtol vapor = ptol vapor/Ptotal
Xben vapor = pben vapor/Ptotal