Question

The equilibrium composition of liquid and vapour in a feed can be identified by,

(a) intersection of q line with equilibrium line

(b) intersection of q line with operating line

(c) intersection of operating line with equilibrium line

(d) None of the mentioned

This question was addressed to me in exam.

My question comes from Flash Vaporization Line (q-line) topic in section Distillation of Mass Transfer

Answer 1

Right option is (a) intersection of q line with equilibrium line

Explanation: If the value of q is between 0 and 1 then the feed has both vapour and liquid. Then the compositions can be identified by intersecting q-line with operating line.