$2{\mathrm{H}}_2+{\mathrm{O}}_2 \to 2{\mathrm{H}}_2\mathrm{O}$ is an example of unbalanced chemical equation.

In the given equation $2{\mathrm{H}}_2+{\mathrm{O}}_2 \to 2{\mathrm{H}}_2\mathrm{O}$, the number of atoms of reactants is equal to the number of atoms on the product side. Like on the reactant side, Hydrogen has 4 atoms and the same number of atoms are on the product side. The same goes for the number of oxygen atoms. Thus, this equation is an example of a balanced chemical equation not an unbalanced equation. So, the given statement is false.