Corrosion of Metals

What is corrosion?

• The process of painting metals to protect them from damage

• The chemical or electrochemical deterioration of metals due to environmental reactions

• The formation of metal alloys to enhance strength

• The melting of metals at high temperatures

Which of the following describes an anode in an electrochemical reaction?

• It gains electrons and undergoes reduction

• It loses electrons and undergoes oxidation

• It remains neutral and does not participate in the reaction

• It is the strongest part of a metal structure

In a corrosion cell, which of the following statements about a cathode is true?

• The cathode gains electrons and does not corrode

• The cathode loses electrons and undergoes oxidation

• The cathode is always made of iron

• The cathode is the site where metal ions dissolve into the solution

Which of the following represents the oxidation reaction for a generic metal (M)?

• M+ne→Mn

• M→Mn+ne−

• Mn+ne−→M

• M+O2→M2O3

When magnesium is connected to a steel water tank, which one becomes the cathode?

• Magnesium

• Steel

• Both corrode equally

• Neither is affected

Why does steel become the cathode when connected to magnesium?

• Magnesium is more reactive and corrodes instead of steel

• Steel is less reactive and therefore oxidizes faster

• Steel releases electrons to protect the magnesium

• Both metals corrode at the same rate

What happens during an oxidation reaction in the corrosion process?

• The metal gains electrons

• The metal loses electrons and forms positive ions

• The metal remains unchanged

• The metal forms a protective oxide layer

Which of the following best describes a reduction reaction?

• It involves the loss of electrons

• It occurs at the anode

• It involves the gain of electrons

• It always results in corrosion

Dry corrosion primarily occurs due to:

• Reaction with oxygen in the absence of moisture

• Reaction with water and dissolved oxygen

• Reaction with acidic solutions

• Reaction with metal salts in seawater

Which of the following statements about wet corrosion is correct?

• It only occurs in marine environments

• It involves an electrochemical process with water acting as an electrolyte

• It occurs faster in dry conditions

• It does not require oxygen