Corrosion of Metals

Which of the following metals is most likely to corrode?

• Aluminium

• Zinc

• Iron

• Gold

An iron nail was placed in different tubes with different conditions. In which tube will the iron rust faster?

What is the chemical formula of the brown flaky substance formed on iron when it corrodes?

• FeO

• FeO₂

• Fe₂O₃

• Fe₃O₂

What is the main chemical equation for the rusting of iron?

• Fe + H₂O → Fe₂O₃

• Fe + O₂ + H₂O → Fe₂O₃·xH₂O

• Fe + O₂ → FeO

• Fe + CO₂ → FeCO₃

Which of the following is not a barrier method of preventing corrosion?

• Oiling

• Greasing

• Plastic coating

• Electroplating with zinc

Which of the following statements correctly explains the principle of sacrificial protection?

• Painting a metal to protect it from corrosion

• Coating iron with plastic to block air
  
  

• Using a more reactive metal to prevent corrosion of a less reactive one

• Mixing two metals to form an alloy

Which of the following metals is used for the sacrificial protection of iron?

• Sodium

• Aluminium

• Lead

• Copper

Which of the following elements is used for both galvanising and sacrificial protection of iron?

• Copper

• Aluminium

• Zinc

• Lead

Zinc used to protect iron from rusting in galvanisation as it is less reactive than iron. True or False?

Which barrier method is most suitable for protecting the chain of a bicycle?

• Painting
  

• Oiling

• Plastic coating

• Painting with gold