Which statement is true?

Which statement is true?

• A. In the corrosion process, it is the cathodic areas or dissimilar cathodic material that corrodes.
• B. In the Galvanic or Electro-Chemical Series for metals, anodic metals are those that will give up electrons most easily.
• C. Both statements are true.
• D. Neither statement is true.

Answer: (B)

In corrosion, oxidation happens at the anodic sites—those metals that tend to lose electrons. When two different metals are joined in an electrolyte, electrons flow from the more active metal to the less active one. The metal that gives up electrons most easily becomes the anode and corrodes, while the more noble metal becomes the cathode and is protected from corrosion. The galvanic or electrochemical series ranks metals by their tendency to lose electrons. Metals that are high in the series (more reactive) are the ones that readily oxidize, so they are the anodic metals. This is why the statement describing anodic metals as those that give up electrons most easily is correct. The opposite idea—that cathodic areas or dissimilar cathodic material would corrode—is not true. Cathodic areas are the sites of reduction and receive electrons; they are protected, not corroding, in a galvanic couple.

In corrosion, oxidation happens at the anodic sites—those metals that tend to lose electrons. When two different metals are joined in an electrolyte, electrons flow from the more active metal to the less active one. The metal that gives up electrons most easily becomes the anode and corrodes, while the more noble metal becomes the cathode and is protected from corrosion.

The galvanic or electrochemical series ranks metals by their tendency to lose electrons. Metals that are high in the series (more reactive) are the ones that readily oxidize, so they are the anodic metals. This is why the statement describing anodic metals as those that give up electrons most easily is correct.

The opposite idea—that cathodic areas or dissimilar cathodic material would corrode—is not true. Cathodic areas are the sites of reduction and receive electrons; they are protected, not corroding, in a galvanic couple.