Q. Which one of the alkali metals forms only the normal oxide, M₂O, on heating in air?
A) Na
B) Rb
C) K
D) Li
Explanation
[Solution from source] Lithium, the smallest alkali metal ion, forms only the normal oxide Li₂O on burning in air. Sodium forms mainly the peroxide Na₂O₂, while potassium and rubidium form superoxides MO₂. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.