Question

In separating two miscible liquids whose boiling points aren50°C and 80°C, the mixture should be to what temperature?

Answer 1

The mixture should be heated to a temperature lying between 50° and 80°C

Answer 2

Answer:

In separating two miscible liquids whose boiling points are 50°C and 80°C, the mixture should be $50^0 \ C$

Explanation:

Miscible liquids :

Those liquids which mix together in all proportions and form a single layer are called miscible liquids.

Example: Alcohol and water are miscible liquids because they mix together in all proportions and form a single layer on mixing. A mixture of miscible liquids is separated by the process of fractional distillation.

2. Immiscible liquids :

Those liquids which do not mix with each other and form separate layers are called immiscible liquids.

Example: Oil and water are immiscible liquids because they do not mix., and form separate layers on mixing. Water being heavier forms the lower layer, and oil being lighter forms the upper layer.  A mixture of immiscible liquids is separated by using an apparatus called a separating funnel.

How can we separate a mixture of two miscible liquids 1(i)   Separation by fractional distillation :

Fractional distillation is the process of separating two (or more) miscible liquids by distillation, the distillate is collected in fractions boiling at different temperatures. A mixture of two miscible liquids can be separated by the process of fractional distillation. The separation of two liquids by fractional distillation depends on the difference in their boiling points. Fractional distillation is carried out by using a fractionating column.

Alcohol and water are miscible liquids. The boiling point of alcohol is 78ºC and the boiling point of water is 100ºC. Since the boiling points of alcohol and water different, therefore, a mixture of alcohol and water can be separated by fractional distillation. The mixture of alcohol and water is heated in a distillation flask fitted with a fractionating column. When the mixture is heated, both alcohol and water form vapors as their boiling points approach. The alcohol vapor and water vapor rise in the fractionating column. The upper part of the fractionating column is cooler, so as the hot vapors rise in the column, they get cooled, condense and trickle back into the distillation flask.