Question

Which of the following metals has more corrosion resistance?

• A. Zinc
• B. Aluminum
• C. Copper
• D. Silver

Hint:

Some of the most reactive metals, like aluminum, can be the most corrosion-resistant because they instantly form a tough, protective "skin" of oxide.

Answer 1

The Correct Option is B

Step 1: Understand corrosion resistance. Corrosion resistance is the ability of a metal to withstand degradation due to chemical reactions with its environment. This is often achieved by forming a stable, protective outer layer.
Step 2: Analyze the corrosion behavior of each metal.

Aluminum: Reacts quickly with oxygen in the air to form a very thin, tough, and transparent layer of aluminum oxide. This passive layer is highly inert and protects the metal from further corrosion.
Zinc: Corrodes in preference to steel (which is why it's used for galvanizing), but the corrosion product is not as stable as aluminum's oxide layer.
Copper: Corrodes slowly to form a distinctive green patina (copper sulfate), which can be protective.
Silver: Tarnishes by reacting with sulfur compounds in the air to form black silver sulfide.
Due to its extremely stable and self-healing passive oxide layer, aluminum has the best overall corrosion resistance among the choices in typical atmospheric conditions.