Class 6 Science – Separation of Substances

1. What purpose does handpicking serve in the process of separation?
(i) Filtration (ii) Sorting (iii) Evaporation (iv) Decantation

Answer: The correct answer is (ii) Sorting.
Handpicking helps to sort and remove unwanted substances when they are visible and large enough to pick by hand.

2. Which of the following substances are commonly separated using the churning method?
(i) Oil from water (ii) Sand from water (iii) Cream from milk (iv) Oxygen from air

Answer: The correct answer is (iii) Cream from milk.
Churning is used to separate cream by spinning milk so the cream collects on top.

3. Which factor is usually essential for the filtration?
(i) Apparatus size (ii) Presence of air (iii) Pore size (iv) Temperature of the mixture

Answer: The correct answer is (iii) Pore size.
Filtration works when the filter has small pores that allow liquid to pass but trap solid particles.

4. State with reasons whether the following statements are True [T] or False [F]. Also, correct the False statement(s).

(i) Salt can be separated from salt solution by keeping it under the Sun. [T]
Answer: True. Water evaporates and salt remains as a solid.

(ii) Handpicking should be used only when the quantity of one component is less. [T]
Answer: True. It works well when the unwanted item is present in a small amount.

(iii) A mixture of puffed rice and rice grains can be separated by threshing. [F]
Answer: False. Correct method is handpicking, not threshing.

(iv) A mixture of mustard oil and lemon water can be separated by decantation. [T]
Answer: True. Oil floats and can be poured off from the top.

(v) Sieving is used to separate a mixture of rice flour and water. [F]
Answer: False. Correct method is filtration, not sieving.

5. Match the mixtures in Column I with their method of separation in Column II.

Column I	Column II
(i) Gram flour mixed with black gram	(d) Sieving
(ii) Chalk powder mixed with water	(e) Filtration
(iii) Corn mixed with potatoes	(a) Handpicking
(iv) Iron powder mixed with sawdust	(b) Magnetic separation
(v) Oil mixed with water	(c) Decantation

6. In what situations would you use decantation instead of filtration to separate solids from liquids?

Answer: Use decantation when solids settle at the bottom. You can pour off the clear liquid from the top easily.

7. Can you relate the presence of nasal hair to any separation process?

Answer: Yes. Nasal hair acts like a filter and blocks dust particles from entering our nose, like filtration works in science.

8. During the COVID-19 pandemic, all of us wore masks. Generally, what material are they made of? What is the role of these masks?

Answer: Masks are made of cloth or non-woven fabric. They filter dust, germs and viruses to protect us from diseases.

9. A mixture containing potatoes, salt and sawdust has been given to you. Outline a stepwise procedure for separating each component from this mixture.

Answer:
1. Handpick the potatoes.
2. Add water — salt dissolves, sawdust floats.
3. Remove sawdust from the top.
4. Evaporate water to get salt.

10. Read the following story titled ‘Intelligent Leela’ and tick the most appropriate options. Provide a suitable title of your choice for the paragraph.

Answer: (Story not provided. Please share it to complete this question.)
Example Title: Leela’s Clever Way of Separation