Page 63 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

Eg: Distillation can be used to separate a
mixture of water (boiling point 100 C) and
o
o
Water outlet acetone (boiling point 56 C).
Condensor
Ordinary water contains many minerals
Water Inlet
dissolved in it. The distilled water used for
injection and in storage battery is produced
by separating these minerals through
distillation.

Fractional Distillation
Fractionating
Column If the boiling points of components have
very small differences, fractional
distillation is to be used to separate them.
See Figure 4.8.
Ethanol (boiling point 78 C) and methanol
o
o
(boiling point 65 C) are two miscible
liquids. There is only a small difference in
their boiling points. These two liquids are
Fig. 4.8 Fractional Distillation
separated from their mixture by fractional
Fractional Distillation of
Crude Oil distillation.
When vapours of the mixture pass through
Crude oil which is drilled out from the depths the fractionating column, repeated
of the earth is a mixture of hydrocarbons liquefaction and vapourisation take place.
which do not have much difference in their
Subsequently, the vapours of low boiling
boiling points. From this, petrol, diesel,
methanol enter the condenser from the
kerosene, naphtha etc., are separated by
fractionating column, condense to liquid
fractional distillation.
and get collected in the round bottomed
flask first. Similarly, ethanol with higher
boiling point can be collected later in
another round bottomed flask.

Petrol Separation using Separating Funnel

Kerosene Fill one-fourth of a bottle with kerosene.
Crude Oil Heavy Oil Pour equal amount of water into it, close
the bottle and shake well. Keep it aside for
Lubricating Oil
a few minutes and observe.
What do you observe?

Furnace

Basic Science VIII
62 62 Basic Science VIII