question_answer 45)

What is the difference between distillation, distillation under reduced pressure and steam distillation?

Answer:

Simple distillation is applied only for volatile liquids which boil without decomposition at atmospheric pressure and contain non-volatile impurities. The distillation under reduced pressure or vacuum distillation is used for those compounds which decomposes at a temperature below their normal boiling points; such compounds cannot be purified by simple distillation. Glycerine is the example of a liquid which decomposes before it boils. Steam distillation is a co-distillation with water and is carried out when a solid or liquid practically insoluble in water, is steam volatile. Steam distillation is based on Dalton's law of partial pressures.