Question #d75c8
1 Answer
The mole fraction of ethylene glycol is 0.414.
Explanation:
Raoult's Law states that the vapour pressure of a solvent in a solution is directly proportional to its mole fraction:
#color(blue)(|bar(ul(color(white)(a/a) P_1 = χ_1P_1^°color(white)(a/a)|)))" "#
where
#P_1# is the vapour pressure of the solvent in the solution#χ_1# is the mole fraction of the solvent#P_1^°# is the vapour pressure of the pure solvent
If the solvent is non-volatile, the formula can be arranged to
#color(blue)(|bar(ul(color(white)(a/a)ΔP = χ_2P_1^°color(white)(a/a)|)))" "#
where
#ΔP"# is the vapour pressure lowering of the pure solvent#χ_2# is the mole fraction of the solute.
The vapour pressure
Our task is to calculate the mole fraction of non-volatile solute (ethylene glycol) that will lower the vapour pressure of the solution to 1 atm at 110 °C.
