To solve this question,we first need to think about the Raoult’s Law which states that the partial vapor pressure of a component in a mixture is equal to the vapor pressure of the pure component at that temperature multiplied by its mole fraction in the mixture.
This means that we need to find the partial pressure for each component of the mixture the add them .
P ether = X ether x Po ether
P ethanol = X ethanol x Po ethanol
Total vapor pressure = P ether + P ethanol
Where P is the partial vapor pressure of the component;X is the mole fraction of the components and Po is the value of vapor pressures of the components when on their own.
Now calculating the moles
moles of ether = 148/74.12 = 1.97 moles
moles of ethanol= 184/46.07 = 3.99 moles
total moles = 1.97 + 3.99 = 5.96 moles
X ether= moles of ether/total moles
X ether = 1.97 / 5.96 = 0.331
X ethanol = 3.99/5.96 = 0.669
Poether = 4.0
Poethanol = 1.1
P ether = 0.331 x 4.0 = 1.324
P ethanol = 0.669 x 1.1 = 0.7359
Total vapor pressure = 1.324 + 0.7359 = 2.0599 = 2.06
Thus the vapor pressure of the solution is 2.06