5. Describe an
experiment to prove that rusting takes place only in moist air.
Answers
Answer:
We take three test tubes and put clean iron nail in each of the them.
1.In the first test tube containing iron nail, we put some anhydrous calcium chloride and closed its mouth with a tight cork. The anhydrous calcium chloride is added to absorb water or moisture from the damp air present in the test tube and make it dry. In this way, the iron nail in the first test tube is kept in dry air. This test tube is kept aside for about half an hour. After one 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.
2.In the second test tube containing iron nail, we put boiled distilled water. Boiled distilled water does 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. In this way, the iron nail in the second test tube is kept in air free, boiled water. The mouth of this test tube is closed with a cork and it is kept aside for about a week. After one 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.
3.In the third test tube containing an iron nail, we put unboiled 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 has been placed in air and water together. The mouth of this test tube is closed with a cork 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 presence of both air and water.
Explanation:
Answer:
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