Which metal is ductile, malleable, resistant to corrosion, and is used for tin-plating for steel food cans against corrosion?

• A. Tin
• B. Lead
• C. Zinc
• D. Bronze

Answer: (A)

The key idea is the combination of forming ability and corrosion resistance needed for a food-contact coating. Tin is soft and highly ductile and malleable, so it can be formed into a very thin, uniform coating on steel to make tinplate. It also provides good corrosion resistance by forming a stable surface, which protects the steel and keeps contents safe from iron contamination. That makes tin ideal for coating steel cans used for food.

Lead is toxic and not used for food contact coatings. Zinc is excellent for general corrosion protection (galvanizing) but isn’t chosen for tin plating in food cans. Bronze is an alloy and not the coating material used for tinplate. Tin’s combination of workability and safety for foods explains why it’s used for tin-plating steel cans.