Final answer:
Zinc is added to base metal alloys to enhance corrosion resistance by forming a protective coating and acting as a sacrificial anode.
Step-by-step explanation:
Zinc is added to base metal alloys like brass and bronze to enhance corrosion resistance. When exposed to air, zinc quickly forms a protective coating of zinc oxide on the surface of the metal, which acts as a barrier to prevent further corrosion. Additionally, zinc can also serve as a sacrificial anode in galvanic protection systems, where it corrodes instead of the base metal, protecting it from corrosion.