Answer:
0.144.
Step-by-step explanation:
- Change in vapor pressure = ΔPsolvent = P of the pure solvent(water) - P of the mixture = 9.21 torr - 7.88 torr = 1.33 torr.
∵ ∆Psolvent = (Xsolute, ethylene glycol)(Pºsolvent, water)
where, Xsolute is the mole fraction of the solute (ethylene glycol).
Pºsolvent is the vapor pressure of the pure solvent = 9.21 torr.
∴ Xsolute = ∆Psolvent / Pºsolvent = (1.33 torr) / (9.21 torr) = 0.144.