A mixture of miscible liquids can be separated through fractional distillation.
True
Oil and water are immiscible. You can easily separate them if you let them stay a while and then decant.
But some liquids get completely mixed together. We can't separate them with methods like decantation. So we need to rely on a different property called the boiling point. If the difference in boiling points is pretty high, we can use distillation. We can easily boil the mixture, get a vapour and then condense it to separate them. But sometimes the boiling points of liquids are very close to each other where even this doesn't work.
So we try to use yet another property like how dense the gas is. Now we can form vapours and let each vapour fall into a compartment where it would get collected. This is why you usually see a setup with many divisions where different gases get collected.
That's fractional distillation.