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=In text questions page number 15

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=In text questions page number 24

=In text questions page number 24

 

In text questions page number 24

In text questions page number 24

1. How will you separate a mixture containing kerosene and petrol (difference in their boiling points is more than 25ºC), which are miscible with each other?
Answer:
kerosene and petrol are miscible liquids also the difference between their boiling point is more than 25 ºC so they can be separated by the method of distillation. Follow the steps given below

(i) Take a mixture in the distillation flask fit it with the thermometer.
(ii) Arrange the apparatus as shown in the given figure.
(iii) Heat the mixture slowly keeping a close watch on thermometer.
(iv) Since the petrol has lower boiling point starts vaporises and condenses in the condenser which is finally collected in the beaker.

Image

2. Name the technique to separate
(i) butter from curd,
(ii) salt from sea-water,
(iii) camphor from salt.
Answer:

(i) Centrifugation
(ii) Evaporation
(iii) Sublimation

3. What type of mixtures are separated by the technique of crystallisation?
Answer:
Crystallisationis a process that separates a pure solid in the form of its crystals from a solution. The crystallisation method is used to purify solids. For example, the salt we get from sea water can have many impurities in it. To remove these impurities, the process of crystallisation is used.



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In text questions page number 24

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