NCERT Exemplar Solutions Class 6 Science Solutions Chapter 5 Separation of Substances

Class 6 NCERT Exemplar Solutions for Science Chapter 5 – Separation of Substances

Question 1.
Paheli bought some vegetables such as french beans, lady’s finger, green chillies, brinjals and potatoes all mixed in a bag. Which of the following methods of separation would be most appropriate for her to separate them?
(a) Winnowing
(b) Sieving
(c) Threshing
(d) Hand picking
Solution:
(d) : Fland picking is the best method for separating the vegetables because they are big in size.

Question 2.
Boojho’s grandmother is suffering from diabetes. Her doctor advised her to take ‘Lassi’ with less fat content. Which of the following methods would be most appropriate for Boojho to prepare it?
(a) Filtration
(b) Decantation
(c) Churning
(d) Winnowing
Solution:
(c) : By churning curd the butter (fat) is separated which can be removed and the remaining lassi contains less fat content.

Question 3.
Which of the following mixtures would you be able to separate using the method of filtration?
(a) Oil in water
(b) Cornflakes in milk
(c) Salt in water
(d) Sugar in milk
Solution:
(b) : Cornflakes are insoluble in milk, hence can be separated by filtration.

Question 4.
Which amongst the following methods would be most appropriate to separate grains from bundles of stalks?
(a) Hand picking
(b) Winnowing
(c) Sieving
(d) Threshing
Solution:
(d): Threshing results in separation of grains from stalks.

Question 5.
Four mixtures are given below.
(i) Kidney beans and chick peas
(ii) Pulses and rice
(iii) Rice flakes and corn
(iv) Potato wafers and biscuits
Which of these can be separated by the method of winnowing?
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iii)
(d) (iii) and (iv)
Solution:
(d): Mixtures of rice flakes and corn and potato wafers and biscuits can be separated by winnowing because there is difference in weight of the two components one being lighter and other being heavier.

Question 6.
While preparing chapatis, Paheli found that the flour to be used was mixed with wheat grains. Which out of the following is the most suitable method to separate the grains from the flour?
(a) Threshing
(b) Sieving
(c) Winnowing
(d) Filtration
Solution:
(b): Flour can be separated from wheat grains by sieving due to difference in size of flour and grain. Wheat grain will not pass through the sieve.

Question 7.
You might have observed the preparation of ghee from butter and cream at home. Which method(s) can be used to separate ghee from the residue?
(i) Evaporation
(ii) Decantation
(iii) Filtration
(iv) Churning
Which of the following combination is the correct answer?
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (ii) and (iv)
(d) (iv) only
Solution:
(b) : Decantation and filtration can be used to separate ghee (which is in liquid form) from the residue (which is in solid form).

Question 8.
In an activity, a teacher dissolved a small amount of solid copper sulphate in a tumbler half filled with water. Which method would you use to get back solid copper sulphate from the solution?
(a) Decantation
(b) Evaporation
(c) Sedimentation
(d) Condensation
Solution:
(b) : When the solution of copper sulphate is evaporated, water evaporates, leaving behind the solid copper sulphate.

Question 9.
During summer, Boojho carries water in a transparent plastic bottle to his school. One day he left his bottle in the school. The bottle still had some water left in it. The following day, he observed some water droplets on the inner surface of the empty portion of the bottle. These droplets of water were formed due to
(a) boiling and condensation
(b) evaporation and saturation
(c) evaporation and condensation
(d) condensation and saturation.
Solution:
(c): Due to high temperature in summers, the water gets heated in plastic bottle and evaporates. The vapours hit the lid of the bottle and condense to form water droplets which get collected on the empty portion of the bottle.

Question 10.
Paheli asked for a glass of water from Boojho. He gave her a glass of ice cold water. Paheli observed some water droplets on the outer surface of the glass and asked Boojho how these droplets of water were formed. Which of the following should be Boojho’s answer?
(a) Evaporation of water from the glass.
(b) Water that seeped out from the glass.
(c) Evaporation of atmospheric water vapour.
(d) Condensation of atmospheric water vapour.
Solution:
(d) : When the air touches the surface of ice cold glass, the water vapours of the atmosphere are condensed to form water droplets on the outer surface of glass.

Short Answer type Questions

Question 11.
Sheela, Saima and Ravi have to dissolve maximum amount of sugar in the same amount of milk so as to win in a game. Ravi took hot boiling milk while Saima took ice cold milk. Sheela managed to get milk at room temperature. Whom do you think would win the game and why?
Solution:
The solubility of solids in liquids increases with temperature. Saima will be able to dissolve minimum amount of sugar in ice cold milk. Sheela will be able to dissolve more sugar than Saima since the milk is at room temperature. Ravi would win the game because he will be able to dissolve maximum amount of sugar in hot boiling milk.

Question 12.
Fill in the blanks with appropriate words.
(i) Small pieces of stone can be removed from rice by_____.
(ii)____ are obtained from stalks by threshing.
(iii) Husk from wheat flour is generally removed by______.
(iv) The process of settling of heavier particles is called_____.

(v) Filtration is helpful in separating an insoluble_______from a______.
Solution:
(i) hand picking
(ii) grains
(iii) sieving
(iv) sedimentation
(v) solid, liquid

Question 13.
State whether the following statements are true or false.
(a) A mixture of oil and water can be separated by filtration.
(b) Water can be separated from salt by evaporation.
(c) A mixture of wheat grains and wheat flour can be separated by sieving.
(d) A mixture of iron filings and rice flour can be separated by magnet.
(e) A mixture of wheat grains and rice flakes can be separated by winnowing.
(f) A mixture of tea leaves and milk can be separated by decantation.
Solution:
(a) False – A mixture of oil and water can be separated by separating funnel.
(b) True
(c) True
(d) True
(e) True
(f) True

Short Answer Type Questions
Question 14.
Name and describe briefly a method which can be helpful in separating a mixture of husk from grains. What is the principle of this method?
Solution:
Husk can be separated from grains by the process of winnowing. When the mixture is allowed to fall down from a height, the lighter husk is carried away by air and fall on the ground. This method is based on the principle that in a mixture with components of different weights, the lighter particles are blown away by wind.

Question 15.
Match the mixtures in column I with their method of separation in column II.

Column 1		Column II
(a)	Oil mixed in water	(i)	Sieving
(b)	Iron powder mixed with flour	(ii)	Hand picking
(0	Salt mixed with water	(iii)	Decantation
(d)	Lady’s finger mixed with french beans	(iv)	Magnet
(e)	Rice flour mixed with kidney beans	(v)	Evaporation

Solution:
(a) – (iii)
(b) – (iv)
(c) – (v)
(d) – (ii)
(e) – (i)

Answer Type Questions

Question 16.
Both Sarika and Mohan were asked to make salt solution. Sarika was given a teaspoonful of salt and half a glass of water, whereas Mohan was given twenty teaspoons full of salt and half a glass of water.

1. How would they make salt solutions?
2. Who would be able to prepare saturated solution?
   Solution:
3. They will mix salt in water and keep stirring it to make a salt solution.
4. Mohan will be able to prepare saturated solution since some salt will be left undissolved after dissolving the maximum salt in water.

Question 17.
Paheli was feeling thirsty but there was only a pot of water at home which was muddy and unfit for drinking. How do you think Paheli would have made this water fit for drinking if the following materials were available to her.
[Alum, tub, muslin cloth, gas stove, thread, pan and lid.] Solution:
With the following materials available to Paheli – alum, tub, muslin cloth, gas stove, thread, pan and lid, she could undertake the following steps to purify water.

1. Filter the muddy water with the help of muslin cloth.
2. Tie the piece of alum with thread and sink in water for some time and then leave water undisturbed.
3. After some time, the impurities will settle down and the water from the top can be decanted.
4. Boil the decanted water for about 10 minutes in a covered pan. Cool and filter the water.
5. The filtered water is fit for drinking.

Question 18.
Read the story titled “WISE FARMER” and tick the correct option to complete the story.
A farmer was sad/happy to see his healthy wheat crop ready for harvest. He harvested the crops and left it under the sun/rain to dry the stalks. To separate the seeds from the bundles of the stalk he hand picked/threshed them. After gathering the seed grains he wanted to separate the stones and husk from it. His wife winnowed/threshed them to separate the husk and later sieved/hand picked to remove stones from it. She ground the wheat grains and steved/filtered the flour. The wise farmer and his wife got a good price for the flour. Can you tell why?
Solution:
(i) sad/_Happy_
(ii) _sun_/rain
(iii) hand picked/_threshed_
(iv) _winnowed_/threshed
(v) sieved/_hand picked_
(vi) _sieved_/filtered
The wise farmer and his wife got a good price for the flour because they used appropriate methods to get good quality of flour.

Question 19.
You are provided with a mixture of salt, sand, oil and water. Write the steps involved for the separation of salt, sand and oil from the mixture by giving an activity along with the diagram.
Solution:
A mixture of salt, sand, oil and water can be separated by following steps.

1. 1. Decant the oil from the mixture which is floating – oil is separated.
      

1. 1. Filter the mixture. Sand will be separated and the filtrate contains salt solution. Sand is separated.
   2. Evaporate the salt solution. Salt is separated.

Question 20.
A mixture of iron nails, salt, oil and water is provided to you. Give stepwise methods to separate each component from this mixture.
Solution:
A mixture of iron nails, salt, oil and water can be separated by the following steps:

1. Hand pick the iron nails or remove by magnet..
2. Remove the oil by decantation or separating funnel.
3. Evaporate the salt and water solution by evaporation. Water can be condensed back and the salt is left behind.

FAQ’s

Can the NCERT Exemplar Solutions for Class 6 Science Chapter 5 be considered as the repository of important questions?

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Can water dissolve any amount of a substance?

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Question: What are the important concepts covered in Chapter 5 of NCERT Exemplar Solutions for Class 6 Science?

Answer: The important concepts covered in Chapter 5 of NCERT Exemplar Solutions for Class 6 Science are –

• Methods of separation
• Hand-picking
• Winnowing
• Threshing
• Sieving
• Sedimentation, Decantation, and Filtration
• Evaporation
• Use of more than one method of separation