Back-trapping in a distillation column?

A liquid is in equilibrium with its vapor at its boiling point. On an average, the molecules in the liquid and gaseous phases have equal________?

With rise in temperature, the solubility of ammonia in water at a fixed pressure________?

Which of the following shows maximum dip effect (indicating reverse direction of temperature change)?

The ratio of the hydraulic radius to the diameter of the channel, for maximum mean velocity of flow in a circular channel, in open channel flow is________?

How many atoms are there per unit cell in a body centred cubic lattice system?