Cathodic protection is best described as which of the following?

• A. A method of coating to prevent rusting
• B. A process that removes rust chemically
• C. A technique using an external current to reduce corrosion
• D. A barrier film that blocks all ion movement

Answer: (C)

Cathodic protection works by making the metal surface the cathode in an electrochemical cell. By applying an external electrical current (or using sacrificial anodes that preferentially corrode), electrons are supplied to the metal, lowering its tendency to oxidize and drastically reducing corrosion. This is different from coatings that simply block rust, chemical rust removal, or barrier films that try to block all ion movement. It’s a deliberate electrochemical method used on submerged or buried structures like pipelines and hulls to protect them from rusting.