Question

A liquid with high boiling point decomposes on simple distillation but it can be steam distilled for its purification. explain how is it possible

Answer 1

The technique of steam distillation is used for separating substances which are immiscible with water, volatile in stem and having high vapour pressure at the boiling temparature of water. If water is used as one of the immiscible liquids then the method is called steam distillation. It is also used for purifying liquids which decompose at their normal boiling point. 
Steam distillation is used for separating organic compounds from plant parts.