The strength of H₂O₂ (g/L) in 11.2 volume solution of H₂O₂ is

Decomposition of H₂O₂:

$2{\mathrm{H}}_2{\mathrm{O}}_2\to 2{\mathrm{H}}_2\mathrm{O}+{\mathrm{O}}_2$

 According to the definition, one liter of 11.2 volume of H₂O₂ gives 11.2 L of oxygen gas. Mass of H₂O₂ present in its one mole is 34 g and the mass of H₂O₂ in two moles is 68 g.

If 68 g of H₂O₂ forms 22.4 L or one mole of oxygen gas, the mass of H₂O₂ required to produce 11.2 L of O₂ gas.

$\begin{array}{ccc}22.4 \mathrm{L} {\mathrm{O}}_2& =& 68 \mathrm{g} {\mathrm{H}}_2{\mathrm{O}}_2\\ 11.2 \mathrm{L} {\mathrm{O}}_2& =& \frac{68 \mathrm{g} {\mathrm{H}}_2{\mathrm{O}}_2}{22.4 \mathrm{L} {\mathrm{O}}_2}\times 11.2 \mathrm{L} {\mathrm{O}}_2\\ & =& 34 \mathrm{g} {\mathrm{H}}_2{\mathrm{O}}_2\end{array}$

Total volume of the solution is 1 L and the strength of H₂O₂ becomes 34 g/L.