Question

Which one of the alkali metals, forms normal oxide $M_{2}O$ on heating in excess of air?

• A. $Li$
• B. $Cs$
• C. $Rb$
• D. $K$

Answer 1

The correct option is A $Li$

On strong heating, only $Li$ gives normal oxide while $K$, $Rb$ and $Cs$ gives superoxide.
$Li\stackrel{O_2}{\to }L{i}_{2}O$
$Cs\stackrel{O_2}{\to }Cs{O}_2$
$Rb\stackrel{O_2}{\to }Rb{O}_2$
$K\stackrel{O_2}{\to }K{O}_2$