Why do vapours condense rapidly and repeatedly when the surface area for condensation is increased?
Increased surface are helps, since the vapor molecules can't pass beyond them, they collide and lose their energy, and condense.
The gas bead packed column is for the vapours of higher boiling liquid, i.e. one which boils at higher temperature than the other. These vapors are required to be condensed and dropped back in the beaker while the vapors of low boiling liquid won't loose energy so easily and will pass on. The condenser is meant for these vapors to cool and collect. Please note that the mixture vaporizes at a range of temperature.
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