A dilute aqueous solution of boric acid, H₃BO₃ is often used as an eyewash. How would you prepare 500.0 mL of a 0.50% (m/v) boric acid solution?

Verified step by step guidance

1. Determine the mass of boric acid needed: Use the formula for mass/volume percent concentration, which is \( \text{\% (m/v)} = \frac{\text{mass of solute (g)}}{\text{volume of solution (mL)}} \times 100\).
2. Rearrange the formula to solve for the mass of boric acid: \( \text{mass of solute (g)} = \frac{\text{\% (m/v)} \times \text{volume of solution (mL)}}{100} \).
3. Substitute the given values into the equation: \( \text{mass of solute (g)} = \frac{0.50 \times 500.0}{100} \).
4. Calculate the mass of boric acid required using the substituted values.
5. Measure the calculated mass of boric acid and dissolve it in enough water to make a total volume of 500.0 mL.

Key Concepts

Concentration (m/v)

Mass/volume (m/v) concentration expresses the mass of solute per 100 mL of solution. A 0.50% (m/v) solution means there are 0.50 grams of solute (boric acid) in every 100 mL of solution. This concept is crucial for understanding how to prepare solutions with specific concentrations.

Dilution

Dilution is the process of reducing the concentration of a solute in a solution, typically by adding more solvent. In this case, to prepare a 0.50% (m/v) solution from a more concentrated stock solution, one must calculate the appropriate volume of stock solution and the amount of water needed to achieve the desired concentration.

Volume Measurement

Accurate volume measurement is essential in preparing solutions. For this task, one must measure 500.0 mL of the final solution using appropriate lab equipment, such as a graduated cylinder or volumetric flask, to ensure the correct concentration of boric acid is achieved.