$5.$The main purpose of reflux in a distillation column is to:

a$)$ Enhance heat transfer

b$)$ Increase column pressure

c$)$ Provide additional driving force for separation

d$)$ Decrease column diameter

Which of the following is not a factor affecting the choice between continuous and batch distillation?

a$)$ Feed composition

b$)$ Separation requirements

c$)$ Column diameter

d$)$ Energy availability

Side streams in distillation columns are typically withdrawn to:

a$)$ Recover valuable components

b$)$ Increase the reflux ratio

c$)$ Improve temperature control

d$)$ Reduce energy consumption

In distillation, the minimum reflux ratio is defined as the reflux ratio:

a$)$ Required for total reflux

b$)$ That achieves the maximum number of theoretical plates

c$)$ That maintains vapor$-$liquid equilibrium

d$)$ Necessary to prevent entrainment of liquid droplets in the vapor