Question 1

Q1: What purpose does handpicking serve in the process of separation? (i) Filtration (ii) Sorting (iii) Evaporation (iv) Decantation

Accepted Answer

Handpicking serves the purpose of (ii) Sorting. Reason: The chapter states that handpicking is done 'on the basis of differences in size, colour and shape of the particles' to remove unwanted components or to select desired ones, which is essentially sorting.

Question 2

Q10: Read the following story titled 'Intelligent Leela' and tick the most appropriate options. Provide a suitable title of your choice for the paragraph....

Accepted Answer

Leela was working in the farm with her father when she realised that they left their drinking water at home. Before her father felt thirsty, she went to the nearby pond to fetch some water. After obtaining some water in the container, she noticed that the water was muddy and unfit for drinking. To p...

Question 3

Q2: 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)...

Accepted Answer

The churning method is commonly used to separate (iii) Cream from milk. Reason: The chapter describes churning curd using a 'mathni' to separate butter, which is essentially cream, from buttermilk. This process separates the lighter butter (cream) that floats to the top.

Question 4

Q3: Which factor is usually essential for the filtration? (i) Apparatus size (ii) Presence of air (iii) Pore size (iv) Temperature of the mixture

Accepted Answer

The factor usually essential for filtration is (iii) Pore size. Reason: The chapter explains that sieving 'allows the fine flour particles to pass through the holes of the sieve' and that 'pores in the cloth can be used as a filter'. It also mentions that 'a filter paper is one such filter that has...

Question 5

Q4: State with reason(s) whether the following statements are True [T] or False [F]. Also, correct the False statement(s). (i) Salt can be separated from...

Accepted Answer

(i) True [T] Reason: The chapter explains that salt is obtained from seawater by keeping it in shallow pits and exposing it to sunlight and air, allowing the water to evaporate completely and leave behind the salt. (ii) True [T] Reason: The chapter states, 'If the particles to be removed are present...

Question 6

Q5: 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 mixed wit...

Accepted Answer

(i) Gram flour mixed with black gram $\rightarrow$ (d) Sieving (ii) Chalk powder mixed with water $\rightarrow$ (e) Filtration (iii) Corn mixed with potatoes $\rightarrow$ (a) Handpicking (iv) Iron powder mixed with sawdust $\rightarrow$ (b) Magnetic separation (v) Oil mixed with water $\rightarrow$...

Question 7

Q6: In what situations would you use decantation instead of filtration to separate solids from liquids?

Accepted Answer

Decantation is used instead of filtration to separate solids from liquids in situations where: 1. The solid component is insoluble and significantly heavier than the liquid, allowing it to settle quickly at the bottom (sedimentation). 2. A complete separation of the solid is not critically required,...

Question 8

Q7: Can you relate the presence of nasal hair to any separation process?

Accepted Answer

Yes, the presence of nasal hair can be related to the filtration process. Similar to how a filter paper or a piece of cloth with fine pores separates impurities, nasal hair acts as a natural filter. It traps dust particles, pollen, and other larger impurities present in the air we breathe, preventin...

Question 9

Q8: During the COVID-19 pandemic, all of us wore masks. Generally, what material are they made of? What is the role of these masks?

Accepted Answer

During the COVID-19 pandemic, masks were generally made of materials such as cloth (like cotton or synthetic fabrics), non-woven fabrics, or specialized filter materials. The role of these masks is to act as a filter. They create a physical barrier with fine pores that help to trap and block the pas...

Question 10

Q9: A mixture containing potatoes, salt and sawdust has been given to you. Outline a stepwise procedure for separating each component from this mixture.

Accepted Answer

To separate potatoes, salt, and sawdust from a mixture, the following stepwise procedure can be used: 1.  Handpicking: First, separate the large pieces of potatoes from the mixture by handpicking them, as they are easily visible and distinct in size and shape. 2.  Dissolving in water: Add water to t...

NCERT Solutions