Question

Amit was asked by his teacher to separate a liquid mixture of acetone and ethyl alcohol. He set up a distillation apparatus and tried to distil the mixture. To his surprise, both the liquids got distilled. Teacher told Amit to repeat the experiment by using a fractionating column in the distillation flask. Amit followed the advice of the teacher and was able to separate the two liquids.
(i) Why was Amit not successful in separating the liquid mixture earlier ?
(ii) Why did teacher ask him to use the fractionating column ?
(iii) Which liquid was distilled first ?
(iv) As a student of chemistry, what value based information you have gathered ?

Answer 1

(i) The difference in boiling point temperatures of acetone `(56^(@)C)` and ethyl alcohol `(78^(@)C)` is only `22^(@)C`. Therefore, process of simple distillation fails in this case.
(ii) Fractionating column is quite effective in this case because it obstructs the distillation of ethyl alcohol which is high boiling and at the same time helps in the distillation of acetone which is low boiling.
(iii) Acetone was distilled first since it has comparatively low boiling point.
(iv) The process of simple distillation can be used in case the liquids present in the mixture differ in their boiling points by at least by `30^(@)C` or more.