How would you balance: ${\mathrm{H}}_2+{\mathrm{O}}_2\to {\mathrm{H}}_2\mathrm{O}$

Balancing the Chemical equation:

• When we balance chemical equations, we want the same number of each sort of atom on both sides of the equation.
• Only the coefficients are changed. The numbers in front of the molecule are called coefficients.
• Subscripts should never be changed.
• Metals must be balanced first, followed by nonmetals such as oxygen and hydrogen.
• The unbalanced chemical reaction provided is

$\underset{\mathrm{Hydrogen}}{{\mathrm{H}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)}$

• The following table shows the number of atoms on each side:

Reactant side	Product side
2 Hydrogen atoms from ${\mathrm{H}}_2$	2 Hydrogen atoms from ${\mathrm{H}}_2\mathrm{O}$
2 Oxygen atoms from ${\mathrm{O}}_2$	1 Oxygen atom from ${\mathrm{H}}_2\mathrm{O}$

• It is a redox synthesis in which Hydrogen ($\mathrm{H}$) and Oxygen ($\mathrm{O}$) are involved.
• As there are two Oxygen atoms on the left side, we must put a $2$ before Water on the right side.
• Now, there are $4$ Hydrogen atoms on the right side, so, we need to put a$2$ before Hydrogen gas on the reactant side.

Reactant side	Product side
4 Hydrogen atoms from ${\mathrm{H}}_2$	4 Hydrogen atoms from ${\mathrm{H}}_2\mathrm{O}$
2 Oxygen atoms from ${\mathrm{O}}_2$	2 Oxygen atoms from ${\mathrm{H}}_2\mathrm{O}$

• Thus, the balanced chemical reaction is:

$\underset{\mathrm{Hydrogen}}{2{\mathrm{H}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to 2\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)}$