Question

2. How will you separate the following mixture?
(a) common salt, sulphur powder and sand. (b) Camphor, common salt and sand.
(c) Water, groundnut oil and common salt.
3. Write the principle of the following techniques and their two applications:
(a) Centrifugation
(b) Chromatography
(c) Crystallisation
4. Why is crystallisation better than simple evaporation? (2 reasons)​

Answer 1

Answer:

(i) Mixture of sand and husk: Sand and husk can be separated by the method of winnowing.

(ii) Mixture of wheat, sugar and silk: For separating silk from the mixture we should follow the winnowing method because silk is lighter than other two components and get separated. Wheat and sugar can be separated by sieving because they are in different sizes.

(iii) Mixture of water and petrol: Water does not dissolve in petrol. So, it can be separated by the use of separating funnel.

(iv) Mixture of rice and salt: Rice and salt can be separated by sieving.

(v) Mixture of sand and salt: Sand and salt is mixed with water, salt dissolves in water and sand can be separated solution by sedimentation and decantation followed by filtration. After that using evaporation common salt is separated.