Purification Of Organic Compounds

Explanation:
A. CHCl₃ + C₆H₅NH (Chloroform + Aniline) — Simple Distillation (IV)

• Chloroform boils at ~61°C

• Aniline boils at ~184°C

• The difference is large enough for simple distillation to separate them because the boiling points are well apart. So, simple distillation is sufficient here, not necessarily vacuum distillation.

B. Crude oil in petroleum industry — Fractional Distillation (III)

• Crude oil contains many hydrocarbons with close boiling points

• Fractional distillation is definitely the method to separate the components efficiently.

C. Glycerol from spent-lye — Distillation under reduced pressure (I)

• Glycerol has a very high boiling point (~290°C) and is thermally sensitive.

• To separate glycerol without decomposition, distillation under reduced pressure (vacuum distillation) is used to lower boiling point.

D. Aniline-water — Steam distillation (II)

• Aniline is partially miscible with water and steam distillation can separate it because steam distillation allows distillation of compounds at temperatures lower than their boiling points.

• Steam distillation is used for temperature-sensitive or immiscible compounds with water.