Question

The purification of drinking water involves
a.Chlorination
b.Filtration
c.Loading
d.Sedimentation
Choose the correct order of these processes
i.a, b, c, d
ii.b, d, c, a
iii.d, b, c, a
iv.d, c, b, a

Answer 1

Chronination is done at the very end during the purification right after the loading of water is done. Sediments are the heavy substances that are present in water bodies.

Complete answer:
Sedimentation is the process in which the heavier particle settles down due to the effect of gravity on them. This is the easiest method and we can observe it in our daily life very easily. If we put some sand and small pebbles in a beaker or jar of water and shake the well. We will now keep this jar on rest for a few minutes. We will see all the particles have settled down. In this way sediments or heavier particles in water are first made to settle down and then further processes are done.
The next step in the purification of water is filtration. There are some particles still left in water which do not settle down or stay suspended in water, which are not healthier for us to consume. Hence these particles are needed to get removed. Filtration is the process of separating the solids which are in suspended form from the liquid using a porous membrane. This membrane will let water pass through it but it does not let smaller particles to pass.
The water is then loaded to the containers through which it is transported to various places around.
After this the chlorine is added to water for its chlorination. It is done to kill the bacteria and microorganisms that are present in the water. It also prevents the spread of water diseases such as typhoid and cholera.
Hence the process of cleaning water is sedimentation, filtration, loading and chlorination.

Thus, the correct option is (iii).

Note:
The filter can be made out of paper, cloth, cotton, slag or glass or any other suitable material. There are certain drawbacks of using chlorine as well because it forms compounds with certain organic compounds present in water mainly trihalomethanes. It also impacts the colour and taste of water.