Question

100 KPa of water vapor at 27^oC is saturated with air in a system, what is the mole fraction of air?

(a) 0.230

(b) 0.306

(c) 0.425

(d) 0.503

I had been asked this question by my college professor while I was bunking the class.

Question is taken from Saturation in section Real Gases: Equations of State, Single Component Two Phase Systems, Saturation & Condensation of Basic Chemical Engineering

Answer 1

Right answer is (d) 0.503

For explanation: Fraction of air = 101.3/(100 + 101.3) = 0.503.