Where are fractions with higher boiling points located in the distillation column?

Where are fractions with higher boiling points located in the distillation column?

• A. At the bottom
• B. At the top
• C. In the middle
• D. Outside the column

Answer: (A)

In distillation, compounds separate by how easily they vaporize. A fractionating column has a temperature gradient: hot at the bottom and cooler as you go up. Vapors rise and separate on trays or packing. The more volatile components, with lower boiling points, tend to stay in the vapor phase and move toward the top. The less volatile components, with higher boiling points, condense earlier and stay lower. So the fractions with higher boiling points are found near the bottom of the column.

In distillation, compounds separate by how easily they vaporize. A fractionating column has a temperature gradient: hot at the bottom and cooler as you go up. Vapors rise and separate on trays or packing. The more volatile components, with lower boiling points, tend to stay in the vapor phase and move toward the top. The less volatile components, with higher boiling points, condense earlier and stay lower. So the fractions with higher boiling points are found near the bottom of the column.