Prevention of Corrosion

Q.

Which metal is used for coating in galvanisation?

1. Lead

2. Mercury

3. Zinc

4. Copper

Q.

_________ is a copper alloy used for making statues.

Q.

Other than iron does any other metal get rusted? If yes, explain how? [3 MARKS]

Q. Alloys generally have which of these characteristics?

1. High melting point and low conductivity
2. High melting point and high conductivity
3. Low melting point and low conductivity
4. Low melting point and high conductivity

Q.

Which among the following alloys contain zinc as one of its constituents?

1. Stainless steel

2. Alnico

3. Brass

4. Nichrome

Q. 1. Define:- with some examples:-
a. Displacement reaction.
b. Ductility.
c. Sonorous .
d. Metalloids.

Q.

Match the alloys of column I with their constituents of column II

Alloys	Constituents
(a) Nichrome	(i) Aluminium + Nickel + Cobalt
(b) Bronze	(ii) Copper + Tin
(c) Alnico	(iii) Nickel + Chromium + Iron

1. (a) - (iii), (b) -(ii), (c) -(i)

2. (a) - (ii), (b) -(iii), (c) -(i)

3. (a) - (iii), (b) -(i), (c) -(ii)

4. (a) - (i), (b) -(ii), (c) -(iii)

Q.

Statement I: Rusting of iron can be prevented by forming a layer of the substance that is chemically inert to the atmosphere.
Statement II: The inert layer prevents the metal from interacting with the atmosphere.

1. Statement I:- False

   Statement II:- False

2. Statement I:- True

   Statement II:- False

3. Statement I:- False

   Statement II:- True

4. Statement I:- True

   Statement II:- True

Q. If gallium exists in liquid form at room temperature.
Than why does an electric soldering wire exists in solid form

Q.

Which of the following statement is/are correct in regard to alloys as compared to pure metals?

1. Low melting point and low conductivity

2. High melting point and low conductivity

3. High melting point and high conductivity

4. Low melting point and high conductivity

Q. If copper is exposed to wet air for an extended period, it develops a greenish coating. Why?

Q. Identify the metal which is found in liquid state at room temperature.

1. Aluminium
2. Mercury
3. Iron
4. Sodium

Q.

Potable water is:

1. Water free from visible impurities
2. Water used for drinking
3. Water free from germs
4. Water not suitable for drinking

Q.

When metal X is alloyed with a non-metal Y, then steel is formed. Identify the metal X and non-metal Y.

1. X:- Iron

   Y:- Silicon

2. X:- Iron

   Y:- Copper

3. X:- Iron

   Y:- Carbon

4. X:- Copper

   Y:- Carbon

Q.

Name the constituents of : Nickel Steel

Q. Assertion :To protect iron from rusting it is coated with a thin layer of zinc. Reason: The zinc forms a barrier against corrosion in that the steel underneath does not come into contact with water / moisture in the air

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q.

What is rust? What is its action on pH paper? [3 MARKS]

Q. Corrosion of iron is essentially an electrochemical phenomenon where the cell reaction are:

1. $Fe$ is oxidised to $F{e}^{2+}$ and dissolved oxygen in water is reduced to $O{H}^{-}$
2. $Fe$ is oxidised to $F{e}^{3+}$ and $H_{2}O$ is reduced to $O_2^{2-}$
3. $Fe$ is oxidised to $F{e}^{2+}$ and $H_{2}O$ is reduced to $O_2^{-}$
4. $Fe$ is oxidised to $F{e}^{2+}$ and $H_{2}O$ is reduced to $O_2$

Q. Statement I: Corrosion occurs when metals are exposed to atmospheric oxygen and water.
Statement II: Galvanisation is the process of applying thin zinc coating over iron articles.

1. Both statements are correct
2. Both statements are incorrect
3. Only statement I is correct
4. Only statement II is correct

Q. If copper is exposed to wet air for an extended period, it develops a greenish coating. Why?

Q. What are the metals that make the alloys brass and bronze? [2 Marks]​

Q.

Which of the following can be used for preventing corrosion?

1. Painting

2. Galvanising

3. Chrome plating

4. All of the given options are correct.

Q. Molten is used for coating iron in galvanisation.

1. iron
2. lead
3. copper
4. zinc

Q.

State the property of lead due to which it is used in making bullets.

Q. Statement I: Corrosion occurs when metals are exposed to atmospheric oxygen and water.
Statement II: Galvanisation is the process of applying thin zinc coating over iron articles.

1. Only statement I is correct
2. Both statements are incorrect
3. Both statements are correct
4. Only statement II is correct

Q.

	X	Y
Normal electronic configuration	2, 8, 7	2, 8, 2
Nature of oxide	Dissolves in water and turns blue litmus red	Very low solubility in water Dissolves in hydrochloric acid
The tendency for Oxidising and reducing reaction	Tends to oxidize elements and compounds	Tends to act as a reducing agent.
Electrical and thermal conductivity	Very poor electrical conductor. Poor thermal conductivity.	Good electrical conductor. Good thermal conductor
Tendency to form alloys and amalgams	No tendency to form alloys form alloys	Form alloys

Using the above information, complete the following:

Non-metallic elements tend to be $\_\_\_$conductors of heat and electricity.

Q.

Potable water is:

1. Water used for drinking
2. Water not suitable for drinking
3. Water free from visible impurities
4. Water free from germs

Q. What is done to prevent the corrosion of metals? ​ [3 Marks]​