Question

Why do we often need to separate mixtures into their constituents?

Answer 1

Separating mixtures

• Constituents of a mixture can be separated with the help of some characteristic property of one constituent that is different from the other constituents in the mixture.
• To separate a mixture of iron filings and sulfur, the characteristic property of iron that is attracted to a magnet is used. Sulfur does not possess this property.
• Thus a magnet can be used to remove iron filings from a mixture of iron and sulfur.

Need for separation

(i) To remove useful components

• In the case of seawater, the objective is to economically recover as much sodium chloride as possible so that it can be used as common salt.
• The focus is on the amount of sodium chloride that can be recovered. It is not our major concern that some sodium chloride may still be left in seawater after the separation.

(ii) To remove undesirable components

• While converting river water to potable water, the objective is to remove undesirable components including dust particles and germs in the water.
• A little wastage of water along with the impurities is affordable. However, there can be no compromise on the quality and purity of water, that is no impurities should remain in the water.

(iii) To get a pure substance

• While producing a medicine, it is essential to remove all harmful impurities from the substance to be used as medicine.
• But in this case, the impurity has to be removed without any loss or wastage of the substance.