Question

The question is taken from Organic Chemistry lab assigment, Simple and Fractional Distillation. There are no tables, plots, or diagrams; just a quesiton.

"Flooding" the packed column during fractional distillation reduces the ability to separate two liquids with similar boiling points. How would a visible liquid phase in the colimn reduce its efficiency?

Answer 1

For efficiency is distillation, the liquid and its vapor must be in equilibrium and the vapor is in constant condensation to liquid and liquid to vapor state (partition) in the distillation column gives maxiumum separation of the components of mixture. Now when we have a visible liquid phase in the column, the column is flooded with the liquid, so no space is left for then liquid to be in equilibrium with its vapor phase. No partitioning occurs in such a case so we would get no separation or minimal separation of components.