Question

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

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

Answer 1

The correct option is D $Li$

When alkali metals heated in atmosphere of oxygen, the alkali metals ignite and form oxides.
Lithium (Li) is the alkali metal which forms only normal oxide, $L{i}_{2}O$ when heated in air.
$2Li+\frac{1}{2}{O}_2\to L{i}_{2}O$
Higher oxides of Li are unstable.

Sodium gives the peroxide, $N{a}_2{O}_2$ and potassium and rubidium give super oxide $\left(M{O}_2\right)$.

Hence, option (b) is correct.