Separation of Substances Test - 5

• To separate solids that are insoluble in liquids and the solid is heavier than the liquid, sedimentation and decantation method is most suited. By leaving the mixture undisturbed for a long time, the larger and heavier solid particles settle down leaving the clear liquid above it. Once the solid has completely settled down, the clear liquid above is poured out leaving behind the insoluble heavy solid particles (decantation). 
• Evaporation cannot be suggested as a method of separation here because it is not mentioned whether the liquid or the solid is volatile or not.
• Filtration is not necessary as the solid particles are heavier and will automatically settle. If the solid particles were not heavy and will not settle down easily, we could have opted for filtration method.
• Condensation and crystallisation method is also not suited because we do not know from the question whether the solid is crystallisable or not.

When a saturated solution is heated, it becomes unsaturated, because it causes an increase in kinetic energy which leads to an increase in distance between the molecules of the liquid. So that the solute particles take free space present in the solvent. 

That is why saturated solution becomes unsaturated on heating.

Hence, option $$(B)$$ is the correct answer.

All the water gets evaporated but this is not suitable for the extraction of sugar. Crystals as the sugar crystals gets charged by heating it in this way. 

Crystallization can be used for separation of a salt from its solution. Crystallisation is a separation technique that is used to separate a solid that has dissolved in a liquid and made a solution. The solution is warmed in an open container, allowing the solvent to evaporate, leaving a saturated solution.

A saturated solution of salt on heating becomes unsaturated solution. On increasing the temperature, larger quantity of salt can be dissolved in water.

A mixture of glucose water can be separated by the method of evaporation. Water being a volatile substance will evaporate and glucose will be left behind. 

Sugar syrup is a saturated solution of sugar.

From sugar syrup, solid sugar separates out as solid cooling and syrup become hard indicating that syrup is a saturated solution.

Seawater is trapped in large, shallow pools and allowed to stand there. The sun’s heat evaporates the water slowly, and common salt is left behind. This salt is further collected, purified, and packed for domestic use. The concentrated brine precipitates the salt, which is then gathered by mechanical harvesting machines. Any impurities that may be present in the brine are drained off and discarded before harvesting.

Bullocks are used for threshing. Threshing is the process which is used to separate grain seeds from stalk.