Our team of subject expert teachers has prepared and reviewed the NCERT Solutions for Class 6 Science Chapter 5 Separation of Substances are given here will help you to prepare well and score good numbers in exams.
Separation of Substances NCERT Solutions for Class 6 Science Chapter 5
Class 6 Science Chapter 5 Separation of Substances Exercise Questions and Answers
Why do we need to separate different components of a mixture? Give two examples.
We carry out the separation of substances for the following purposes:
- To remove the unuseful or harmful component: For example, removing tea leaves after making tea.
- To obtain the useful component: For example, getting wheat, rice grains after separating husk, dirt, etc.
- To remove impurities for getting a pure sample: For example, obtaining sugar crystals from jaggery (gur) or salt from seawater.
What is winnowing? Where is it used?
Winnowing is a method of separation which is used to separate lighter and heavier components of a mixture. It is used by farmers to separate the husk from grains in a field. The farmer allows the mixture of grain and the husk to fall from a height. The grains which are heavier fall vertically down on the ground. The husk which is lighter is carried away by the wind and forms a separate heap at a short distance from the heap of grain.
How will you separate husk or dirt particles from a given sample of pulses before cooking?
Husk or dirt particles from pulses can be separated by handpicking method.
What is sieving? Where is it used?
Sieving is a method of separation used when the components of a mixture are of different sizes. Sieving the wheat flour through a sieve allows fine particles of the flour to pass through the holes of the sieve while the bigger husk particles remain on the sieve.
How will you separate sand and water from their mixture?
Take a beaker (100 ml) half-filled with a given sample of water. Stir the water thoroughly. Now keep the beaker undisturbed for some time. Sand gets settled down at the bottom of the beaker. After some time, water can be separated by the decantation process and sand is left in the beaker.
Is it possible to separate sugar mixed with wheat flour? If yes, how it is possible?
Yes, it is possible to separate sugar mixed with wheat flour by sieving.
How would you obtain clean water from a sample of muddy water?
We can purify the muddy water by loading. First, we take a beaker (100 ml) half-filled with muddy water. Now take a piece of alum (phitkari) and a thread (about 30 cm in length). Tie firmly the one end of the thread with alum and hold the other end of the thread with your hand.
Now dip the alum in the water and move it slowly in a circular path for about one minute. Remove the alum and keep the beaker undisturbed for some time. During this process, we will find that the dust particles get loaded and become heavier and settle down at the bottom of the beaker quite rapidly. When all the dust particles settle down, the water becomes clear. The clear water is then decanted into another beaker.
Fill in the blanks :
(a) The method of separating seeds of paddy from its stalks is called _________.
(b) When milk is poured onto a piece of cloth the cream (malai) is left behind on it. This process of separating cream from milk is an example of _________.
(c) Salt is obtained from seawater by the process of _________.
(d) Impurities settled at the bottom when muddy water was kept overnight in a bucket. The clear water was then poured off from the top. The process of separation used in this example is called _________.
Sedimentation and Decantation
True or False :
(a) A mixture of milk and Water can be separated by filtration.
(b) A mixture of powdered salt and sugar can be separated by the process of winnowing.
(c) Separation of sugar from tea can be done with filtration.
(d) Grain and husk can be separated with the process of decantation.
Lemonade is prepared by mixing lemon juice and sugar in water. You wish to add ice to cool it. Should you add ice to the lemonade before or after dissolving sugar? In which case would it be possible to dissolve more sugar?
We should add ice to lemonade after dissolving sugar. Without ice, sugar dissolves easily in lemon juice, because solubility depends on the temperature. If sugar is added to an ice-cold solution of sugar and lemon juice, the solubility of sugar will decrease.