There is a sample of 10 volume of hydrogen peroxide solution. Calculate its strength.

$$\begin{gathered} \left[{\mathrm{H}}_2{\mathrm{O}}_2 \to {\mathrm{H}}_2\mathrm{O} + \frac{1}{2} {\mathrm{O}}_2 \right]\times 2 \\ \underset{68 \mathrm{g}}{2{\mathrm{H}}_2{\mathrm{O}}_2} \to {\mathrm{H}}_2\mathrm{O} +{\mathrm{O}}_2 22.4 \mathrm{litres} \mathrm{at} \mathrm{N}.\mathrm{T}.\mathrm{P}. \\ \because 22.4 \mathrm{litres} {\mathrm{O}}_2 \mathrm{at} \mathrm{N}.\mathrm{T}.\mathrm{P}. \mathrm{obtained} \mathrm{by} 68 \mathrm{g} \mathrm{of} {\mathrm{H}}_2{\mathrm{O}}_2 \\ \therefore 10 \mathrm{litres} {\mathrm{O}}_2 \mathrm{at} \mathrm{N}.\mathrm{T}.\mathrm{P}. \mathrm{obtained} \mathrm{by} \\ \frac{68}{22.4} \times 10 = 30.35 \mathrm{g} /\mathrm{litre} \\ \therefore 1000 \mathrm{ml} {\mathrm{O}}_2 \mathrm{at} \mathrm{N}.\mathrm{T}.\mathrm{P}. \mathrm{obtained} \mathrm{by} =30.35 \mathrm{g} \\ \therefore 100 \mathrm{ml} {\mathrm{O}}_2 \mathrm{at} \mathrm{N}.\mathrm{T}.\mathrm{P}. \mathrm{obtained} \mathrm{by} \\ \frac{30.35}{1000} \times 100=3.035\% \end{gathered}$$