CBSE · NCERT · Class 6 Science · Chapter 9

NCERT Solutions: Class 6 Science Chapter 9 - Methods of Separation in Everyday Life

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Chapter-wise NCERT intext questions and exercise answers for Methods of Separation in Everyday Life, grounded in the official textbook.

Questions are taken verbatim from the NCERT textbook; answers were grounded against the chapter's content during generation. Items needing review are marked.
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Q.1What purpose does handpicking serve in the process of separation? (i) Filtration (ii) Sorting (iii) Evaporation (iv) Decantationv
  1. i. Filtration
  2. ii. Sorting
  3. iii. Evaporation
  4. iv. Decantation
Solution

Handpicking separates visible solid components by sorting them manually on the basis of differences such as size, colour or shape.

Answer:

(ii) Sorting

Q.2Which 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 airv
  1. i. Oil from water
  2. ii. Sand from water
  3. iii. Cream from milk
  4. iv. Oxygen from air
Solution

Churning is used to separate butter or cream from curd or milk.

Answer:

(iii) Cream from milk

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

Filtration works because the pores of the filter allow smaller particles or liquid to pass through while retaining larger insoluble particles.

Answer:

(iii) Pore size

Q.4State 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 salt solution by keeping it under the Sun. (ii) Handpicking should be used only when the quantity of one component is less. (iii) A mixture of puffed rice and rice grains can be separated by threshing. (iv) A mixture of mustard oil and lemon water can be separated by decantation. (v) Sieving is used to separate a mixture of rice flour and water.v
Solution

Evaporation under the Sun leaves salt behind. Handpicking is suitable when one visible component is present in smaller quantity. Threshing is for separating grains from stalks. Decantation can separate immiscible liquids or a settled mixture. Sieving separates dry solids of different particle sizes, not flour mixed with water.

Answer:

(i) True. (ii) True. (iii) False. A mixture of puffed rice and rice grains can be separated by handpicking or by winnowing, depending on the difference in size and weight. Threshing separates grains from stalks. (iv) True. (v) False. Rice flour and water can be separated by filtration or sedimentation followed by decantation, not by ordinary sieving.

Q.5Match 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 with water (iii) Corn mixed with potatoes (iv) Iron powder mixed with sawdust (v) Oil mixed with water. Column II: (a) Handpicking (b) Magnetic separation (c) Decantation (d) Sieving (e) Filtrationv
Solution

Sieving separates dry solids of different particle sizes. Filtration separates insoluble solids from liquids. Handpicking separates visible solid pieces. Magnetic separation removes magnetic material. Decantation separates immiscible liquids such as oil and water.

Answer:

(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.

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

Decantation depends on sedimentation. Filtration is needed when fine insoluble particles remain suspended and do not settle easily.

Answer:

Use decantation when the solid is insoluble, heavier than the liquid, and settles at the bottom after standing. Then the clear liquid can be poured off carefully. It is useful when the particles are large or heavy enough to settle and filtration is not necessary.

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

This is similar to filtration, where a filter allows air to pass but holds back some solid particles.

Answer:

Yes. Nasal hair works like a natural filter. It traps dust and larger particles from the air before the air goes deeper into the respiratory system.

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

Like a filter, a mask lets air pass through but blocks many larger droplets and particles.

Answer:

Masks are generally made of cloth or non-woven fabric. Their role is to act as filters that reduce the spread of droplets, dust and some disease-causing particles between people.

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

The procedure uses different properties: size for handpicking potatoes, solubility for dissolving salt, insolubility of sawdust for filtration/skimming, and evaporation to obtain salt from salt solution.

Answer:

First, remove the potatoes by handpicking because they are large and visible. Next, add water to the remaining salt and sawdust mixture. Salt dissolves in water, while sawdust remains insoluble and mostly floats. Separate the sawdust by filtration or careful skimming. Finally, evaporate the salt solution to recover salt.

Q.10Read the following story titled 'Intelligent Leela' and tick the most appropriate options. Provide a suitable title of your choice for the paragraph. 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/hungry, she went to the nearby pond to fetch some water/grains. After obtaining some water in the container, she noticed that the water was muddy and fit/unfit for drinking. To purify the water, she kept it for some time and then she filtered/churned the muddy water using a piece of paper/muslin cloth. Leela, then, cooled/boiled the water for about 10 minutes in a covered pan. After cooling/boiling, she filtered/churned it again and made it fit/unfit for drinking. She served this water to her father while having food, who blessed her and appreciated her efforts.v
Solution

The story describes making pond water safer by allowing mud to settle, filtering through cloth, boiling to kill germs, cooling, and filtering again before drinking.

Answer:

The correct options are: thirsty, water, unfit, filtered, muslin cloth, boiled, cooling, filtered, fit. A suitable title is 'Leela Makes Muddy Water Safe'.