the vapour pressure of pure liquid benzene and toluene are 160mm and 60 mm repectively. calculate the vapour pressure of an equimolar solution at the same temperature?
To calculate the vapor pressure of an equimolar solution of benzene and toluene, you need to apply Raoult's Law. According to Raoult's Law, the total vapor pressure (Ptotal) of the solution is the sum of the partial pressures (P1 and P2) of the individual components (benzene and toluene) multiplied by their mole fraction (X1 and X2) in the solution.
Mathematically, Raoult's Law can be expressed as:
Ptotal = P1 * X1 + P2 * X2
In this case, the solution is equimolar, meaning the mole fraction of benzene (X1) and toluene (X2) is both 0.5.
Given:
P1 (vapor pressure of benzene) = 160 mm
P2 (vapor pressure of toluene) = 60 mm
X1 (mole fraction of benzene) = 0.5
X2 (mole fraction of toluene) = 0.5
Now, substitute these values into the equation:
Ptotal = 160 mm * 0.5 + 60 mm * 0.5
Simplifying the equation:
Ptotal = 80 mm + 30 mm
Therefore, the vapor pressure of the equimolar solution at the same temperature is 110 mm.