#### Answer

0.022 mol

#### Work Step by Step

Given that mass percent= 3.0%.
This implies that 3.0 g of $H_{2}O_{2}$ is present in 100g of the solution. In 25.0g of the solution $\frac{3.0}{4}g$ is present, i.e., 0.75 g is present.
Number of moles of $H_{2}O_{2}$=
Mass in grams$\div$ Molar mass= $\frac{0.75g}{34.0147g/mol}= 0.022 mol$