Question

what does this set up show?​

Answer 1

Answer:

Answer = calcium chloride and boiled water .

Answer 2

It is an experiment to show that air and moisture both are necessary for rusting:

1st Test Tube:

The first test tube containing iron nail, we put some anhydrous calcium chloride and closed its mouth. After a week we observe that there is no rust on the surface of iron nail. This shows that rusting of iron does not take place in air alone.

2nd Test Tube:

In the second test tube containing iron nail, we put boiled distilled water. Boiled distilled water does not contain any dissolved air or oxygen in it. a layer of oil is put over boiled water in the test tube to prevent the outside air from mixing with boiled water. Test tube is closed and after a week, we observe that no rust is there on the surface of iron nail. This shows that rusting of iron does not take place in water alone.

3rd Test Tube:

In the third test tube containing an iron nail, we put on boiled water so that about two-thirds of the nail is immersed in water and the rest is above the water, exposed to damp air. In this way, the iron nail have been placed in air and water together. The mouth of this test tube is closed and it is kept aside for about a week. After one week we observe that red brown rust is seen on the surface of iron nail kept in the present of both air and water.

so this set up show that both air and moisture is necessary for the rusting.

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