(N/A) The oxidation number method can be explained by the following steps:
Step-$1$: Write the correct chemical formula for each reactant and product.
Step-$2$: Identify the atoms that undergo a change in oxidation number by assigning oxidation numbers to all elements in the reaction.
Step-$3$: Calculate the increase or decrease in the oxidation number per atom and for the entire molecule or ion. If the total increase and decrease are not equal,multiply by suitable coefficients to make them equal.
Step-$4$: Account for the involvement of ions if the reaction takes place in an aqueous medium. Add $H^{+}$ or $OH^{-}$ ions to the appropriate side so that the total ionic charges on both sides are balanced. Use $H^{+}$ for acidic solutions and $OH^{-}$ for basic solutions.
Step-$5$: Balance the number of hydrogen atoms by adding water $(H_{2}O)$ molecules to the reactants or products. Finally,verify the number of oxygen atoms. If the number of oxygen atoms is equal on both sides,the equation is balanced.