Question

If the area under the curve of \(\frac{1}{-r_A} \) versus XA for a PFR used to carry out an autocatalytic reaction is 5\((\frac{m^3 s}{mol}),\) then the ratio of change in volume to molar feed rate is ____

(a) 5

(b) 10

(c) 15

(d) 20

This question was posed to me during a job interview.

Enquiry is from Autocatalytic Reactions topic in portion Potpourri of Multiple Reactions, Design for Single & Parallel Reactions of Chemical Reaction Engineering

Answer 1

Right choice is (b) 10

The best explanation: For a PFR,

FA0dXA=(-rA)dV

The area under the curve of \(\frac{1}{-r_A} \)versus XA = \(\frac{dXA}{(-rA)} = \frac{dV}{F_{A0}}\) = 5.