Rusting

Q.

What is the definition of rusting?

Q. an alloy of iron and carbon was treated with sulphuric acid in which only iron react . if a sample of alloy weighing 140gm gave 6gm of hydrogen . what is the percentage of iron in the alloy?

Q.

Explain how painting ofan iron gate prevent it from rusting

Q.

Why are Iron pipes used In homes to carry water galvanised?

Q.

Write the difference between pig iron cast iron and steel.

Q.

Name two conditions which are essential for rusting. Write the chemical equation for rusting of Iron. [2 MARKS]

Q. Why iron pillar in qutub minar has not rusted?

Q.

Which of the following is not a necessary requirement for rusting?

1. Both A and B

2. Oxygen

3. Moisture

4. Heat

Q. (1) Give an example for each of the following with proper explanation:

a) A physical change which is reversible.
b) A chemical change in which change of colour is observed.

(2) How would you show that setting of curd is a chemical change? [3 MARKS]

Q. Can we prevent rusting by applying a layer of grease on the iron?Why?

Q.

What Is Metal Coupling?

Q.

Which of the following alloy is used in making the bodies of aeroplanes?

1. Stainless steel

2. Brass

3. Bronze

4. Duralumin

Q.

Question 6

Iron pillar near the Qutub Minar in Delhi is famous for the following facts. Which of these facts is responsible for its long stability?
(a) It is more than 7 m high
(b) It weighs about 6000 kg
(c) It was built more than 1600 yrs ago
(d) It has no rust after such long period

Q.

Define Rusting and how can we prevent rusting? [3 MARKS]

Q.

Question 21

If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
(a) Do you think rust is different from iron?
(b) Can you change rust back into iron by some simple method.
(c) Do you think formation of rust from iron is a chemical change?
(d) Give two other examples of a similar type of change.

Q.

The nature of anti-rust solution is$\mathrm{\_\_\_\_\_\_\_\_\_\_\_}$

Q.

Compare cast iron, steel and wrought iron.

Q.

Question 9
Explain how the painting of an iron gate prevents it from rusting.

Q.

Which are the methods used for prevention of corrosion?

1. Painting

2. Galvanization

3. Alloying

4. None of these

Q.

1.What is cathode and Anode?

Q.

1: Decomposition of solid ammonium chloride is associated with____________ change.

Q.

Question 5

A man painted his main gate made up of iron, to

(i) prevent it from rusting.
(ii) protect it from the sun.
(iii) make it look beautiful.
(iv) make it dust free.

Which of the above statement(s) is/are correct?
(a) (i) and (ii)
(b) (ii) and (iii)
(c) only (ii)
(d) (i) and (iii)

Q. is commonly known as rust.

1. Iron oxide
2. Copper oxide
3. Silver oxide

Q. The image given below is example of

1. Physical change
2. Chemical Change
3. Brown colour paint
4. Reversible Change

Q.

Iron is a hard metal but still, its alloy steel is used in building bridges. Why?

Q.

Why is brass not suitable for type making?

Q. State two differences between rusting and burning.

Q.

Explain why the iron articles are galvanized?

Q.

Write a note on the three varieties of iron.

Q.

Why are the lower parts of ships and bridges coated with coal tar?