1. The problem is to calculate the weight/volume percentage (\% w/v) of iron (Fe) in a solution. 2. The formula for weight/volume percentage is: $$\% \mathrm{w/v} = \frac{\text{mass of solute (g)}}{\text{volume of solution (mL)}} \times 100\ \mathrm{mL}$$ 3. Given: mass of Fe = 0.1123 g, volume of solution = 25.0 mL. 4. Substitute the values into the formula: $$\% \mathrm{w/v} = \frac{0.1123\ \mathrm{g}}{25.0\ \mathrm{mL}} \times 100\ \mathrm{mL}$$ 5. Calculate the division: $$\frac{0.1123}{25.0} = 0.004492$$ 6. Multiply by 100 mL: $$0.004492 \times 100 = 0.4492\%$$ 7. Round to three significant figures: $$0.449\%$$ Therefore, the weight/volume percentage of Fe in the solution is 0.449%.