Question

Sodium burns in excess air to give mainly:
$(A)N{a_2}O$
$(B)Na{O_2}$
$(C)N{a_2}{O_2}$
$(D)NaH$

Answer 1

Hint: When any element is burnt in air, then it will react with the components present in the air. So the element will react with oxygen present in the air and form different oxides in different amounts. Different oxides are formed due to the fact that element and oxygen combine in different ratios or proportions.

Complete answer:
We know that when any compound or element is burnt in air, it reacts with the gases or components that are present in air. The most reactive gas present in air is oxygen. So, elements generally combine with oxygen present in air to form the oxides. These oxides can be of different types because elements and oxygen combine with each other in different proportions.
The oxides can be of different types according to their formula and structure. They can be peroxide (in which there are two oxygen atoms bonded together in a compound), superoxide or simple oxide (in which oxidation state is usual).
So, if we consider the alkali metals, they are famous to make these different types of oxides when they combine with oxygen.
Sodium metal when burned in excess air, forms sodium peroxide with chemical formula $N{a_2}{O_2}$ .
Hence, the correct option is (C) ,$N{a_2}{O_2}$ .

Note:
Like sodium forms sodium peroxide when burnt in excess air, lithium also forms Lithium peroxide. Rubidium when burned in excess air forms Rubidium superoxide. Superoxides when hydrolysed gives peroxides and oxygen molecules. Magnesium when burned in air forms Magnesium oxide.