Corrosion and Its Prevention

Q. Which of the following metals do not undergo corrosion?

1. Iron
2. Gold
3. Copper
4. Silver

Q. How is an iron gate prevented from rusting? (2 marks)
[APSCERT Textbook]

Q. During corrosion, iron reacts with which of the following substances that are present in the atmosphere?

1. Oxygen
2. Moisture
3. Nitrogen
4. Carbon dioxide

Q. Which of the following are true in the case of corrosion?

1. Causes metals to shrink
2. Damages things made up of metals
3. Increases strength of metals
4. Metal strength remains unaffected

Q. Iron articles are shiny when new, but get coated with a reddish brown layer when left in open for a long time.

1. True
2. False

Q. Which of the following metal is used to coat iron articles during galvanisation?

1. Lead
2. Mercury
3. Zinc
4. Copper

Q. A shiny brown metal X when exposed to the atmosphere undergoes corrosion and develops a greenish layer Y on its surface. Identify X and Y.

1. X: Copper
   Y: Copper sulphate
2. X: Copper
   Y: Copper carbonate
3. X: Iron
   Y: Iron oxide
4. X: Iron
   Y: Iron hydroxide

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

Q. Iron when reacts with moist air forms a reddish brown layer of iron oxide which is known as rust.

1. True
2. False

Q. Statement I: If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.

Statement II: Rusting of iron is a chemical change.

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