Question

A process is carried out for the feed mixture of 40% air and 60% oxygen, the compressor recovered 2% of oxygen, what is the exit pressure of the compressor, if the partial pressure of oxygen vapor is 5 mm Hg?

(a) 2.4 mm Hg

(b) 4.8 mm Hg

(c) 6.5 mm Hg

(d) 8.4 mm Hg

This question was posed to me during an interview for a job.

Origin of the question is Condensation topic in portion Real Gases: Equations of State, Single Component Two Phase Systems, Saturation & Condensation of Basic Chemical Engineering

Answer 1

Right option is (a) 2.4 mm Hg

Easy explanation: Exit components, oxygen: 0.6*0.98 = 0.588, air: 0.4, => yoxygen= 0.588/0.988 = 0.595, => Total exit pressure = 5/0.595 = 8.4 mm Hg.