This can be done by dissolving both of them in water. Sugar gets dissolved in water while or chalk is insoluble in water.

Decantation is a method of separation used after sedimentation in which when insoluble particles settle down, the clear liquid is poured into another container

A saturated solution of a substance is the one in which no more of that substance can be dissolved.

To separate harmful or non-useful substances and to obtain the useful component.

It is not correct as when a hot saturated solution is cooled, crystals will be formed.

Following steps are used to separate a mixture of
saw dust and sugar :
(i) Add water to the mixture 
(ii) Sugar present in the mixture dissolves in water but saw dust does not.
(iii) The solution is then filtered through filter paper.
(iv) We will get sugar solution as filtrate and saw dust will remain on the filter paper.
(v) Then the solution is heated and when water evaporates completely, sugar is left behind

Sea water is allowed to stand in shallow pits. Due to solar heat, water in the pits get evaporated. After some days, the water evaporates completely and the solid salts remain in the pits. These salts are further purified to get pure common salt

Sieving is a process used for separating solid components of mixtutres varying in size.
It allows the fine particles to pass through the holes of the .sieve while the bigger particles remain on the sieve. It is used to separate pebbles and stones from the sand

When a mixture is allowed to stand for some time, the heavier components in the mixture settle at the bottom and the process is called sedimentation. For example, when mixture of sand and water is allowed to stand for some time, the particles of sand settle down at the bottom of vessel. The settling down of sand particles is called sedimentation.

Since, clothes may have small holes but filter papers do not have any holes, in fact it has very fine pores in it, hence sand particles settle down on the filter paper while water after very neat pouring reached to vessel.

The method to separate each component from the mixture is given below:
(i) Hand picking: It is used to separate iron nails from the mixture.
(ii) Decantation: The mixture is allowed to stand for some time. The clear liquid is poured to another container to separate oil from the mixture.
(iii) Evaporation: The remaining liquid is allowed to evaporate till residue is obtained. This residue is salt.

A mixture of salt, sand, oil and water can be separated by following steps:
Step I : First of all, the clear liquid is poured into another container by the process of decantation. By this process, oil is separated from the mixture.
Step II : Now filter the mixture by using filter paper, funnel and container by the process of filtration. By this process, sand is separated from the mixture 

Step III : Finally, the remaining liquid evaporates till the residue in obtained by the process of evaporation. By this process, salt is separated from the mixture.

(a) This is done as follows:
(i) Some water is added to the mixture of sand and salt in a beaker and stirred. Salt dissolves in water to form salt solution, whereas sand remains undissolved. It is then filtered.
(ii) On filtering, sand is obtained as a residue on the filter paper and salt solution is obtained as a filtrate. (iii) The filtrate is evaporated and pure salt is left behind.
(b) The mixture of sand and salt has been separated into its components, i.e sand and salt by doing two methods.
(i) Filtration
(ii) Evaporation
(c) Rohit is knowledgeable and intelligent boy.

Paheli can make this water fit for drinking by work on following sequence:
Filtration using muslin cloth (cotton fabric).
                         \(\downarrow\)
Swirl with alum and leave water undisturbed for some time.
                          \(\downarrow\)
The clear liquid above the impurities is poured in another container(decantation).
                           \(\downarrow\)
Boil for 10 min in covered pan with lid.
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Cool, filter and now, it is fit for drinking.