How can you show that air and water are necessary for rusting
Answers
Answer:
Take three test tubes and place clean iron nails in each of them.
Label these test tubes A, B and C. Pour some water in test tube A and cork it.
Pour boiled distilled water in test tube B add about 1 ml of oil and cork it. The oil will float on water and prevent the air from dissolving in the water.
Put some anhydrous calcium chloride in test tube C and cork it. Anhydrous calcium chloride will absorb the moisture if any from the air. Leave these test tubes for a few days and then observe.
Observation : Iron nails rust in test tube A but they do not rust in test tubes B and C. In the test tube A, the nails are exposed to both air and water. In the test tube B the nails are exposed to only water and the nails in test tube C are ex¬posed to dry air.
Inference : From this we can conclude that both air and water are necessary for corrosion of iron.
Put one nail exposed only to air. You will see that it does not get rust.
Put another nail in water and don’t allow the water to pass thru it. You will observe that it will not get any rust.
Put the third nail in water and also exposed to air. After some days, you will see that the nail is rusted and has got weaken.