Multiple choice

Which of the given metals do not burn in air but can form a deposit of oxide layer on its surface?

  1. Copper

  2. Potassium

  3. Sodium

  4. Silver

  5. Magnesium

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The metals Iike iron, lead and copper do not burn in air. Instead they get covered with an oxide layer that is insoluble in water. When copper oxidizes it forms a very thin layer of copper oxide on the outer surface of the copper that further protects the surface from oxidation. This layer is greenish in colour and is called patina.