Question

Demonstrate that moisture and oxygen in air is necessary for corrosion

Answer 1

Answer-

Aim : demonstrate that air and moisture and necessary for rusting.

Materials required: three test tubes, 3 Iron nails, calcium chloride, water, test tube Stoppers.

Procedure:

1. take three test tubes with one iron nail in each and mark them as a b and C
2. place a small amount of calcium chloride in the test tube to dry the air
3. in the test tube be with boil water. boiling of water drives out all the dissolved oxygen from water.
4. put some tap water in the test tube c.
5. close the mouth of all the three test tubes with Stoppers.
6. leave the set up undisturbed for 3 to 4 days.

Observation : the nails In A and B test tubes are free from rust while that in the test tube she has rusted.

Inference: Oxygen and moisture are two necessary requirement for rusting. test tube a lacks moisture while test tube b in lacks air, thus nail in these test tubes are not rusted. in the test tube c both oxygen and moisture are present that make the iron nail rusted.

Answer 2

Answer:

Aim: to show that air and water are necessary for rusting.

Explanation:

• Take 3 test tubes and place 3 clean iron nails in each of them.
• Label these test tubes as A, B and C.
• Pour some water in Test tube A and cork it.
• Pour boiled distilled water in test tube B. (Boiling remover air dissolved in water)
• Pour 1ml of oil in test tube B and cork it.The oil will float on water and prevents the air from entering
• Pour some anhydrous calcium choride in the test tube C and cork it. Anhydrous Calcium chloride will absorb moisture, if any, from the air.

• Leave these tubes for a few days and then observe.
• You will observe that the nails in test tube A, but they don't rust in test tubes B and C.
• In test tube A, the nails were exposed to both air and water.
• In test tube B the nails are only exposed to water, and in Test tube C, the nails are only exposed dry air.

This shows that both oxygen and water are necessary for iron to rust.