NIOS Class 10 Science Activity 27.2 Solution |Metals and Non-Metals

NIOS Class 10 Science Activity 27.2 explains the experiment to demonstrate the conditions required for the rusting of iron. We have discussed metallic lustre in activity 27.1. Rusting affects the metallic lustre.

Metals and Non-Metals Activity Solution

This activity is based on the NIOS Class 10 science and technology (212) Chapter 27- Metals and Non-Metals Module 6- Natural Resources.

 

NIOS Class 10 Science Activity 27.2

Aim

To demonstrate the conditions necessary for the rusting of iron.

Materials Required

   1. Iron nails (3)

   2.  Three test tubes

   3. Distilled water

   4. Anhydrous calcium chloride

   5. Corks

   6. Labels or markers

Procedure

We take three clean, dry test tubes and label them A, B, and C. We put one clean iron nail in each test tube. In test tube A, we add distilled water until half of the nail is immersed, then close the test tube with a cork.

In test tube B, we add distilled water in excess so that the nail is completely immersed in water and close the tube tightly to prevent contact with air.

In test tube C, we add anhydrous calcium chloride along with an iron nail and close it with a cork.

We keep these three test tubes for some days, and after that, observe the nails.

Observation

Test tube	Condition	Observation
A	Nail partly in water and partly exposed to air	Maximum rusting occurs
B	Nail is completely immersed in water, but no air	No rusting
C	Dry air with calcium chloride	No rusting

 

We can see a reddish-brown flaky powder forming on the nail in the test tube A. This substance is called rust.

Explanation

Rusting occurs when both air (oxygen) and moisture are present. In test tube B, only water is present but no air is present, so rusting does not occur.

In test tube C, air (oxygen) is present, but moisture is absent, so rusting does not occur.

In test tube A, both moisture and air(oxygen) are present, so rust occurs.

Chemical Reaction of Rusting

4Fe +3O₂ →2Fe₂O₃.xH₂O

Rust is known as hydrated iron (III)oxide.

Conclusion

This activity shows that rusting of iron occurs when both oxygen and moisture are present together. If either oxygen or moisture is absent, rusting does not take place. Rust is a reddish-brown, flaky substance formed on iron.

Methods to Prevent Rusting

Rusting  can be prevented by following:

    1. Painting iron surfaces

    2. Oiling and greasing metal parts.

    3. Galvanisation (coating iron with zinc)

    4. Alloying

Frequently Asked Questions

Q1. What is rust?

Answer- Rust is reddish brown substance formed when iron reacts with oxygen and moisture.

Q2. What are the conditions required for rusting?

Answer- Rusting occurs only when oxygen and moisture are present together.

Q3. Why was calcium chloride used in test tube?

Answer- Calcium chloride is used to absorb moisture.

Q4. Why did rusting occur in test tube A?

Answer- Because both air and water were present in test tube A.

Q5. What is the formula of rust?

Answer - Fe₂O₃.xH₂O

Multiple Choice Questions

Q1. Rusting of iron requires:

(a)       Oxygen only

(b)      Moisture/water only

(c)       Both oxygen and moisture

(d)      None of the above

Correct answer – (c ) -

 

Q2. Which substance absorbs moisture in activity 27.2?

(a)       Sodium chloride

(b)      Calcium chloride

(c)       Calcium carbonate

(d)      Copper sulphate

Correct answer- (b)

Q3. In which test tube did maximum rusting occur?

(a)       Test tube A

(b)      Test tube B

(c)       Test tube C

(d)      None

Correct answer –(a)

Q4. Rust is chemically known as:

(a)       Iron oxide

(b)      Hydrated iron (III) oxide

(c)       Ferric chloride

(d)      Iron carbonate

Correct answer- (b)

Q5. Which method helps prevent rusting

(a)       Heating

(b)      Cooling

(c)       Painting

(d)      Cutting

Correct answer – (c)