Question With Answer Class 6 Science Chapter 9

Chapter 9 of Class 6 Science, Methods of Separation in Everyday Life, explains the basic features that make an organism live. Through simple questions and answers, students can easily understand this chapter.

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1. What purpose does handpicking serve in the process of separation?

(i) Filtration
(ii) Sorting
(iii) Evaporation
(iv) Decantation

Answer:
✔ (ii) Sorting

Explanation:
Handpicking is used for sorting unwanted solid materials by hand, such as removing stones from rice.

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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:
✔ (iii) Cream from milk

Explanation:
Churning is used to separate cream (or butter) from milk or curd.

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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:
✔ (iii) Pore size

Explanation:
In filtration, the pore size of the filter paper or cloth is important because it allows liquid to pass while stopping solid particles.

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

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(i) Salt can be separated from salt solution by keeping it under the Sun.

✔ True (T)

Reason:
Water evaporates in sunlight and salt remains behind.

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(ii) Handpicking should be used only when the quantity of one component is less.

✔ True (T)

Reason:
Handpicking is suitable when the unwanted substance is present in small quantity and is clearly visible.

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(iii) A mixture of puffed rice and rice grains can be separated by threshing.

❌ False (F)

Correct Statement:
A mixture of puffed rice and rice grains can be separated by handpicking or winnowing, not by threshing.

Reason:
Threshing is used to separate grains from stalks, not two solid food items.

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(iv) A mixture of mustard oil and lemon water can be separated by decantation.

✔ True (T)

Reason:
Mustard oil and lemon water do not mix and form two layers. The upper layer (oil) can be separated by decantation.

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(v) Sieving is used to separate a mixture of rice flour and water.

❌ False (F)

Correct Statement:
Filtration is used to separate a mixture of rice flour and water.

Reason:
Sieving is used to separate solids of different sizes, not solid from liquid.

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

Column I

(i) Gram flour mixed with black gram
(ii) Chalk powder with water
(iii) Corn mixed with potatoes
(iv) Sawdust with water
(v) Oil mixed with water

Column II

(a) Handpicking
(b) Magnetic separation
(c) Decantation
(d) Sieving
(e) Filtration

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Answer (Matching):

(i) Gram flour mixed with black gram → (d) Sieving
(ii) Chalk powder with water → (e) Filtration
(iii) Corn mixed with potatoes → (a) Handpicking
(iv) Sawdust with water → (c) Decantation
(v) Oil mixed with water → (c) Decantation

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Explanation:

• Gram flour and black gram → Different particle sizes, so sieving is used.
  
• Chalk powder and water → Solid insoluble in water, so filtration.
  
• Corn and potatoes → Large visible particles, so handpicking.
  
• Sawdust and water → Sawdust floats; liquid can be poured off by decantation.
  
• Oil and water → Two immiscible liquids, separated by decantation.
  

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

Answer:
Decantation is used when:

• The solid particles are heavy and settle down at the bottom (sedimentation).
  
• The liquid above becomes clear and can be poured off easily.
  

Example:
Separating muddy water after the mud settles down.

We use decantation instead of filtration when filtration is not necessary and the solid has already settled.

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

Answer:
Yes. Nasal hair works like filtration.

It traps dust particles and other impurities present in the air and prevents them from entering our lungs.

So, nasal hair acts like a natural filter.

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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 generally made of:

• Cotton cloth
  
• Surgical fabric
  
• Non-woven fabric
  

Role of masks:

• They filter tiny droplets and dust particles.
  
• They prevent viruses from entering or spreading.
  
• They act like a filtration barrier.
  

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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 (Stepwise Procedure):

Step 1: Handpicking
Remove potatoes by hand because they are large and easily visible.

Step 2: Add water to the remaining mixture (salt + sawdust)
Salt dissolves in water, but sawdust floats.

Step 3: Decantation
Remove floating sawdust from the top.

Step 4: Evaporation
Heat the salt solution. Water evaporates and salt remains behind.

Thus, all three components are separated:

• Potatoes → by handpicking
  
• Sawdust → by decantation
  
• Salt → by evaporation