The weight of H₂O₂ present in 10 ml 80Vol. H₂O₂ solution is

80 volume strength of H₂O₂ solution means

1 ml of H₂O₂ solution $\stackrel{\mathrm{produces}}{\to }$80 ml of O₂

10 ml of H₂O₂ solution $\stackrel{\mathrm{produces}}{\to }$ ??? ml of O₂

$\frac{10\times 80}{1}=$800 ml of  O₂

800ml of O₂ liberated from 10ml of 80 vol strength of H₂O₂ solution.

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

2 x 34 gr of H₂O₂ solution ------22.4 lit (22400ml)  of O₂

 ??? gr of H₂O₂ solution ----------800 ml of  O₂

 $\frac{800\times 2\times 34}{22400}= 2.42\mathrm{gms}$of H₂O₂ solution

The weight of H₂O₂ present in 10 ml 80 vol. strength of H₂O₂ solution is 2.42gr