In fractional distillation, I understand that the vapor travels up the fractiona
ID: 1044890 • Letter: I
Question
In fractional distillation, I understand that the vapor travels up the fractionating column which then encounters cooler surfaces. Upon this, the rising vapors condense and the newly condensed liquid is then reheated by more rising vapors and revaporizes.
What I don't get is this.
If the condensed liquid is revaporized, how would it continue to travel upwards?
Like, wouldn't it just be an endless cycle of condensation and revaporization in the fractionating column - in the same position?
I feel like the explanation is so simple, but I just don't get it.
Please help, will thumbs up! Thanks for your help in advance.
Explanation / Answer
Fractional distillation is one of the analytical technique for purification and separation of mixture of components which are not having widely different boiling points. The fractional distillation set up comprises of a heat source, distilling flask, fractionating column, condenser and a collecting flask. The mixture of components continuously boils at distilling flask and vapour starts to move upward through fractionating column. The fractionating column is a long vertical tube through which vapour passes upward and partially condenses. The condensed liquid comes back to boiling flask to repeat the same process. Inside the column the returning liquid is getting contacted with vapour which is moving upward and heat interchange occurs. And thereby the vapour get enriched with the more volatile component. The vapour which reaches the top of the column is passes through the condenser. The condenser is connected to fractionating column in horizontal direction. The condensed liquid collects in a flask.
This is the principle and working of fractional distillation technique. The condensed liquid which is collected in the flask is not again vaporizes. But the partially condensed liquid in the column is returning back to the boiling flask and again vaporizes. The partial condensation of liquid inside the column is because it contains mixture components. While returning back it get enriches with more volatile component by its mixing with the vapour. The thorough mixing of returning liquid and vapour gives effective fractional distillation.