Question

Fractional Distillation lab

1) What type of bond does Fractional distillation break?

2)What type of bond was re-formed when the vapor condensed in your collection flask?

3)What peaks in the IR spectra allow you to clearly distinguish acetone from 2-propanol,

4)Of the different type of distillation that your practiced in lab (simple and fractional) which one was more efficient in getting pure acetone?

5)What is the significance of an taller condenser in fractional distillation?

Answer 1

1) Fractional distillation is used to separate low boiling liquids that have close boiling points. Non polar liquids which are associated by weak vanderwalls bonds or dipole dipole bonds are broken in fractional distillation.

2)The same bonds are reformed during condensation.

3) acetone will show strong peak at 1720 cm^-1 corresponding to carbonyl absorption. However propanol show no such peak instead a strong peak at 3400 cm^-1 for O-H stretching will be observed.

4. Simple distillation is more efficient in getting pure liquids because of greater difference in boiling points between the two liquids.

5) taller condenser aid in better separation of liquids because the high boiling component can easily get condensed back when it passes through a longer column than a shorter one.