# NEET Chemistry The s-Block Elements Questions Solved

Sodium looses its lustre on exposure to air due to formation of-

(A) NaOH and $N{a}_{2}C{O}_{3}$

(B) $N{a}_{2}O$ and NaOH

(C) $N{a}_{2}O$ and $N{a}_{2}C{O}_{3}$

(D) NaOH and $N{a}_{2}C{O}_{3}$

(A). In air, a layer of $N{a}_{2}O$, NaOH and $N{a}_{2}C{O}_{3}$ is formed on its surface which loses its lustre.

$4Na+{O}_{2}\to 2N{a}_{2}O\stackrel{2{H}_{2}O}{\to }4NaOH\stackrel{2C{O}_{2}}{\to }2N{a}_{2}C{O}_{3}+2{H}_{2}O$

Difficulty Level:

• 42%
• 24%
• 27%
• 9%