Why are packed and spinning band fractional distillation columns more efficient than unpacked columns?

Answer 1

A packed fractional distillation column will be more effective at separating two closely boiling liquids than an empty one because you have more surfaces for condensation and revaporization of the liquid. A packed fractional distillation column has many more surfaces two allow the mixture of vapors to condense and distill again over and over to effectively separate.

Answer 2

A packed fractionating column is more efficient than an unpacked one because it provides a large surface area for heat exchange between the ascending vapor and the descending liquid. This allows for multiple, successive condenstations and distillations and produces better separation between liquids.

Reference: Macroscale and Microscale Organic Experiments, Williamson, pg. 89

Answer 3

because with fractional distillation it is possible to separate a mixture of liquids whose boiling points are quite close together

Answer 4

Packed and spinning band fractional distillation allow for a greater surface area which improves separation.