Answer: Option (b) is the correct answer.
Explanation:
As per law of conservation of mass, mass of a substance cannot be created or destroyed as it can simply be transformed from one form to another.
For example, [tex]2Na_{2}O \rightarrow 4Na + O_{2}[/tex]
There are in total 4 sodium atoms and 2 oxygen atoms on reactant side. Whereas there are 4 sodium atoms and 2 oxygen atoms on product side.
Since, number of atoms on both reactant and product side are equal. Hence, mass on both reactant and product side will be equal in nature.
Therefore, this equation is a balanced equation.
Thus, we can conclude that in the given equation Na = 4, O = 2; Na = 4, O = 2; yes, this equation does follow the law of conservation of mass.
