Q1: Which of the following materials does not form adherent oxide film on surface ?

ANS:D - Gold & silver

Gold and silver do not form adherent oxide films on their surfaces under normal atmospheric conditions. Copper, nickel, and aluminum are known to form oxide films on their surfaces when exposed to air. These oxide films can provide protection against further oxidation and corrosion. Gold and silver are noble metals and are relatively inert, meaning they do not readily react with oxygen or other elements in the atmosphere to form oxides. Instead, they typically remain in their metallic state and are known for their resistance to corrosion and tarnishing.