NCERT Activity 3.14 Class 10 Science Explanation

We will explore the necessary conditions required for rusting of iron in this activity.

Aim of the activity

To determine the essential conditions for rusting of iron

Materials Required

   1.  Three clean iron nails

   2. Three test tubes

   3. Water (distilled & normal )

   4. Oil

   5. Calcium chloride

   6.  Corks

Procedure

We take three test tubes and label them A, B and C and place a dry iron nail in each test tube.

(i)      We pour ordinary water in the test tube A and cork it.

(ii)   We pour boiled distilled water in the test tube and also add 1 ml of oil and cork it.

(iii)   We add anhydrous calcium chloride in the test tube C and cork it.

Now we leave the all-test tubes for 3-4 days and observe the iron nails.

 

Observation

Test tube	Contents	Observation
A	Iron nail + air + water	Rust occurs
B	Iron nail+  boiled water+  oil	No rust
C	Iron nail + anhydrous CaCl2	No rust

 

Explanation

Rusting of iron requires both moisture (water) and oxygen (air)

Rusting occurs in the test tube A because both air and moisture present. A reddish brown flaky layer is formed on the nails.

 

4Fe+ 3O₂ + xH₂O → 2Fe₂O₃.xH₂O

 

 Water is present in the test tube B but air is blocked by oil layer so no rusting occurs.

 Dry air is present in the test tube C because calcium chloride absorbs moisture, so no rusting occurs.

 Conclusion

 This activity demonstrates that rusting of iron takes place when both air and moisture are present.

 Frequently Asked Questions

    1. What is rusting?

Answer- Rusting is a slow oxidation of iron occurs in the presence of air and moisture.

    2. What is the chemical formula of rust?

Answer- Fe₂O₃.xH₂O

    3. Why is calcium chloride used in this activity?

Answer- Calcium chloride absorbs moisture.