A ideal binary mixture of ethanol and water has a mole fraction of ethanol of 0.4. The total pressure of the solution at 298 K is 1 atm. The vapour pressure of pure ethanol and pure water at 298 K are 0.98 atm and 0.95 atm, respectively. Assume that the mixture behaves ideally.
What is the partial pressure of ethanol in the vapour phase above the solution?
In an ideal solution, the partial pressure of a component in the vapour phase above the solution is equal to the product of its mole fraction in the liquid phase and the vapour pressure of the pure component. Therefore, the partial pressure of ethanol can be calculated as:
Therefore, the correct answer is option (1).