Question

Balance the following chemical equations?

${\mathrm{Na}}_2{\mathrm{O}}_2+{\mathrm{H}}_2\mathrm{O}\to \mathrm{NaOH}+{\mathrm{O}}_2$

Answer 1

Steps involved in balancing a chemical equation are as follows:

• Write the chemical equation in the form of a word equation. Keep the reactants on the left side and the products on the right side. Separate them by an arrow$\left(\to \right)$, whose head points from the reactants towards the products.
• Convert the word equation into the symbol equation by writing the symbols and formulae of all the reactants and products.
• Make the atoms of different elements on both sides of the equation equal by a suitable method. This is known as the balancing of equations.
• Do not change the formulae of the substances while balancing the equation.
• Make the equation more informative if possible.

Balancing of the equations is done in the following steps

Step 1: Calculating the number of atoms of all the elements in the reactants and products

$\underset{\mathrm{Sodium}\mathrm{peroxide}}{{\mathrm{Na}}_2{\mathrm{O}}_2\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Sodium}\mathrm{Hydroxide}}{\mathrm{NaOH}\left(\mathrm{aq}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}$

Element	Reactant side	Product side
Na	2	1
H	2	1
O	3	3

Thus, the number of H atoms is equal on both sides. At the same time, the number of ‘Fe’ and ‘O’ atoms is not equal.

Step 2: To balance the Sodium, put coefficient 4 before $\left(\mathrm{NaOH}\right)$ on the product side and 2 before $\left({\mathrm{Na}}_2{\mathrm{O}}_2\right)$ in reactant side.

$\underset{\mathrm{Sodium}\mathrm{peroxide}}{2{\mathrm{Na}}_2{\mathrm{O}}_2\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Sodium}\mathrm{Hydroxide}}{4\mathrm{NaOH}\left(\mathrm{aq}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}$

Step 3: In order to equate Hydrogen and oxygen atoms, put coefficient 2 before water on the reactant side.

$\underset{\mathrm{Sodium}\mathrm{peroxide}}{2{\mathrm{Na}}_2{\mathrm{O}}_2\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Sodium}\mathrm{Hydroxide}}{4\mathrm{NaOH}\left(\mathrm{aq}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}$

Step 4: On final inspection, the number of atoms of all the elements on both sides of the equation is equal. Therefore, the equation is balanced.

$\underset{\mathrm{Sodium}\mathrm{peroxide}}{2{\mathrm{Na}}_2{\mathrm{O}}_2\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Sodium}\mathrm{Hydroxide}}{4\mathrm{NaOH}\left(\mathrm{aq}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}$