Answer: Option (c) is the correct answer.
Explanation:
A chemical equation will be balanced when there are equal number of both reactants and products.
For example, [tex]Na + Cl_{2} \rightarrow NaCl[/tex] is an unbalanced chemical equation.
As there are two molecules of Cl on reactant side and there is only one molecule of Cl present on product side.
Therefore, to balance this chemical equation we will place the numbers in front of molecules as follows.
[tex]2Na + Cl_{2} \rightarrow 2NaCl[/tex]
Thus, we can conclude that a chemical equation is balanced by changing or adding numbers in front of molecules.
